研究者情報

マスター

アカウント（マスター）

• 氏名

  島田　敏宏(シマダ　トシヒロ), シマダ　トシヒロ

所属（マスター）

• 工学研究院　応用化学部門　無機材料化学分野

所属（マスター）

• 工学研究院　応用化学部門　無機材料化学分野

独自項目

syllabus

• 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, electronic materials and devices, thermoelectrics, solar cells, hard materials, solid state physics
• 2021, 応用物質化学（機能固体材料化学）, Applied Materials Chemistry (Functional Solid State Materials Chemistry), 修士課程, 総合化学院, electronic materials and devices, thermoelectrics, solar cells, hard materials, solid state physics
• 2021, 応用化学特別講義, Advanced-Applied Chemistry, 修士課程, 総合化学院, materials informatics, python
• 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, materials informatics, python
• 2021, 実践的計算化学, Practical Computational Chemistry, 修士課程, 総合化学院, 計算化学、理論化学、分子軌道法、密度汎関数法
• 2021, 大学院共通授業科目（一般科目）：自然科学・応用科学, Inter-Graduate School Classes(General Subject):Natural and Applied Sciences, 修士課程, 大学院共通科目, Photofunctional molecules, Semiconductor, Quantum chemical calculation, Nanomaterial, Catalyst, Energy source, Diffusion, Reaction
• 2021, 総合化学特論Ⅰ(Modern Trends in Physical and Material Chemistry), Modern Trends in Physical and Material Chemistry, 修士課程, 総合化学院, Photofunctional molecules, Semiconductor, Quantum chemical calculation, Nanomaterial, Catalyst, Energy source, Diffusion, Reaction
• 2021, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, electronic materials and devices, thermoelectrics, solar cells, hard materials, solid state physics
• 2021, 先端総合化学特論Ⅱ, Modern Trends in Chemical Sciences and Engineering II, 博士後期課程, 総合化学院, materials informatics, python
• 2021, 先端総合化学特論Ⅰ, Modern Trends in Chemical Sciences and Engineering I, 博士後期課程, 総合化学院, Photofunctional molecules, Semiconductor, Quantum chemical calculation, Nanomaterial, Catalyst, Energy source, Diffusion, Reaction
• 2021, 物質変換工学, Applied Chemistry and Biochemistry, 学士課程, 工学部, 有機合成，有機材料，化学プロセス，反応器設計，生体材料，高分子材料，分子機能，無機材料，複合材料，電子材料，光機能材料
• 2021, 物性化学, Materials Physical Chemistry, 学士課程, 工学部, 熱力学・統計力学　量子力学　電磁気学　固体物性　機能材料　生体機能

PositionHistory

• 大学院総合化学院副学院長, 2020年4月1日, 2021年3月31日
• 評価室室員, 2014年7月1日, 2016年6月30日
• 評価室室員, 2016年7月1日, 2018年6月30日

researchmap

プロフィール情報

学位

• 博士（理学）（東京大学）

プロフィール情報

• プロフィール

  2010年4月から北海道大学・大学院工学研究院・物質化学部門・固体反応化学研究室

• 姓

  島田, シマダ

• 名

  敏宏, トシヒロ

• ID各種

  201201076448891313

対象リソース

http://kaken.nii.ac.jp/d/r/10262148.ja.html

業績リスト

研究キーワード

• エピタキシ-   有機半導体   炭素材料   結晶成長   エピタキシャル成長   酸化物   層状物質   光電子分光   

研究分野

• ものづくり技術（機械・電気電子・化学工学） / 電子デバイス、電子機器
• ナノテク・材料 / 結晶工学
• ナノテク・材料 / 応用物性
• ナノテク・材料 / ナノマイクロシステム
• ナノテク・材料 / ナノバイオサイエンス
• ナノテク・材料 / ナノ材料科学
• ナノテク・材料 / ナノ構造物理
• ナノテク・材料 / ナノ構造化学

経歴

• 2010年04月 - 現在 北海道大学 工学(系)研究科(研究院) 教授
• 2000年04月 - 2010年03月 東京大学 准教授
• 1998年10月 - 2000年03月 東京大学 講師
• 1993年11月 - 1998年10月 東京大学 助手

委員歴

• 2013年04月 - 現在   日本化学会   Chemistry Letters編集委員
• 2013年04月 - 現在   日本セラミックス協会   部会地区幹事
• 2009年04月 - 現在   電気学会   調査研究委員会委員長/幹事
• 2023年01月 - 2025年12月   IUVSTA Electronic Materials and Processing Diviison   Secretary
• 2018年11月 - 2019年10月   SSDM   Area Vice Chair
• 2016年11月 - 2018年10月   SSDM   Area Chair
• 2013年04月 - 2017年03月   応用物理学会   分科会幹事
• 2007年04月 - 2009年03月   応用物理学会   分科代表プログラム委員・講演会企画運営委員

論文

• Synthesis and electron-transporting properties of phenazine bisimides

  Keita Tajima, Taito Moribe, Kyohei Matsuo, Hiroko Yamada, Shu Seki, Seiya Yokokura, Toshihiro Shimada, Norihito Fukui, Hiroshi Shinokubo

  Journal of Materials Chemistry C in press 2024年12月
• Thermodynamic efficiency of membrane separation of dilute gas: Estimation for CO2 direct air capture application

  Masaki Kato, Teruki Ando, Cho Rong Kim, Seiya Yokokura, Hiroki Waizumi, Toshihiro Shimada

  Journal of Membrane Science Letters 4 2 100085 - 100085 2024年12月
• Solvent-vapor-assisted crystallization of covalent organic framework films for CO2/CH4 separation

  Masaki Kato, Takashi Yanase, Hiroki Waizumi, Seiya Yokokura, Toshihiro Shimada

  Chemistry Letters 53 10 2024年10月04日 

  Abstract Covalent organic framework films were prepared using alternating vapor deposition of precursors followed by solvent vapor annealing. When an as-deposited film was annealed in appropriate solvent vapors, the prepared covalent organic framework film exhibited an “onion-like” structure. This result opens a way to synthesize covalent organic framework films with highly ordered planar layers through the interaction between layers. The CO2/CH4 separation performance of covalent organic framework film was significantly improved due to the decrease in defects caused by crystallization.
• Stress-Induced Martensitic Transformation in Na3YCl6

  Akira Miura, Koki Muraoka, Kotaro Maki, Saori Kawaguchi, Kazuhiro Hikima, Hiroyuki Muto, Atsunori Matsuda, Ichiro Yamane, Toshihiro Shimada, Hiroaki Ito, Yoshikazu Mizuguchi, Chikako Moriyoshi, Hiroshi Nakajima, Shigeo Mori, Hiroshi Oike, Akira Nakayama, Wenhao Sun, Nataly Carolina Rosero-Navarro, Kiyoharu Tadanaga

  Journal of the American Chemical Society 146 36 25263 - 25269 2024年09月11日 

  Martensitic transformation with volume expansion plays a crucial role in enhancing the mechanical properties of steel and partially stabilized zirconia. We believe that a similar concept could be applied to unexplored nonoxide materials. Herein, we report the stress-induced martensitic transformation of monoclinic Na3YCl6 with an ∼3.4% expansion. In situ synchrotron X-ray diffraction and atomistic simulations showed that anisotropic crystallographic transformation from monoclinic to rhombohedral Na3YCl6 occurs exclusively under uniaxial pressure; no effect is observed under hydrostatic pressure conditions. The uniaxially pressed powder compact of monoclinic Na3YCl6 showed a large indentation impression and low Young’s modulus, in contrast to its high bulk modulus, suggesting that these unique mechanical properties are induced by the martensitic transformation.
• Low-Frequency Raman Spectroscopy on Amorphous Poly(Ether Ether Ketone) (PEEK)

  Tomoko Numata, Naomoto Ishikawa, Toshihiro Shimada, Keith C. Gordon, Makoto Yamaguchi

  Materials 17 15 3755 - 3755 2024年07月30日 

  Low-frequency peaks in the Raman spectra of amorphous poly(ether ether ketone) (PEEK) were investigated. An amorphous sample with zero crystallinity, as confirmed by wide-angle X-ray diffraction, was used in this study. In a previous study, two peaks were observed in the low-frequency Raman spectra of the crystallized samples. Among these, the peaks at 135 cm−1 disappeared for the amorphous sample. Meanwhile, for the first time, the peak at 50 cm−1 was observed in the crystallized sample. Similar to the peak at 135 cm−1, the peak at 50 cm−1 disappeared in the amorphous state, and its intensity increased with increasing crystallinity. The origins of the two peaks were associated with the Ph-CO-Ph-type intermolecular vibrational modes in the simulation. This suggests that the Ph-CO-Ph vibrational mode observed in the low-frequency region of PEEK was strongly influenced by the intermolecular order.
• Pitched π-Stacking Crystal Structure and Two-Dimensional Electronic Structure of Acenaphtho[1,2-k]fluoranthene Analogues with Various Substituents

  Takuma Yuki, Seiya Yokokura, Mingoo Jin, Hiroki Waizumi, Taro Nagahama, Toshihiro Shimada

  Crystal Growth & Design 2024年02月21日
• High-pressure phase and pressure-induced phase transition of Ag3YCl6

  Kotaro Maki, Koki Muraoka, Saori Kawaguchi, Taku Tanimoto, Akira Nakayama, Seiya Yokokura, Toshihiro Shimada, Kiyoharu Tadanaga, Akira Miura

  CrystEngComm 2024年
• Unidirectional growth of epitaxial tantalum disulfide triangle crystals grown on sapphire by chemical vapour deposition with a separate-flow system

  Takashi Yanase, Miu Ebashi, Kotaro Takamure, Wataru Ise, Hiroki Waizumi, Akira Chikamatsu, Yasushi Hirose, Toshihiro Shimada

  CrystEngComm 2024年 [査読有り]
  
• Single Crystal Growth of Cyclopenta-Fused Polycyclic Aromatic Hydrocarbon by the Naphthalene Flux Method: 2D Ambipolar Charge Transport Properties and NIR Absorption

  Hirohiko Tanoguchi, Takuma Yuki, Seiya Yokokura, Takashi Yanase, Mingoo Jin, Hajime Ito, Taro Nagahama, Toshihiro Shimada

  ACS Applied Electronic Materials 2023年11月28日
• Intrinsic Magnetic Proximity Effect at the Atomically Sharp Interface of Co _x Fe_3-x O₄/Pt Grown by Molecular Beam Epitaxy

  Shoto Nodo, Ichiro Yamane, Motohiro Suzuki, Jun Okabayashi, Seiya Yokokura, Toshihiro Shimada, Taro Nagahama

  ACS OMEGA 8 28 24875 - 24882 2023年07月 

  Co (x) Fe3-x O4(CFO)/Pt bilayers prepared by molecularbeam epitaxywere investigated for the anomalous Hall effect and X-ray magneticcircular dichroism (XMCD). We found that the anomalous Hall effectoriginates from a magnetic proximity effect at the CFO/Pt interface.The XMCD signal in the Pt L-edge was obtained onlyfor the sample deposited at 600 & DEG;C, indicating that the magneticproximity effect is sensitive to the interface structure. Transmissionelectron microscopy images of the CFO/Pt interface and XMCD measurementsof Co and Fe L-edges do not provide direct evidencefor interfacial atomic diffusion or alloying. In summary, these resultssuggest that the magnetic proximity effect is robust for transportproperties, such as the anomalous Hall effect, while the induced magneticmoment depends on slight differences in the interfacial structure,such as the presence or absence of interfacial oxygen ions.
• Band Structure Evolution during Reversible Interconversion between Dirac and Standard Fermions in Organic Charge-Transfer Salts

  Ryuhei Oka, Keishi Ohara, Kensuke Konishi, Ichiro Yamane, Toshihiro Shimada, Toshio Naito

  Magnetochemistry 9 6 153 - 153 2023年06月09日 

  Materials containing Dirac fermions (DFs) have been actively researched because they often alter electrical and magnetic properties in an unprecedented manner. Although many studies have suggested the transformation between standard fermions (SFs) and DFs, the non-availability of appropriate samples has prevented the observation of the transformation process. We observed the interconversion process of DFs and SFs using organic charge-transfer (CT) salts. The samples are unique in that the constituents (the donor D and acceptor A species) are particularly close to each other in energy, leading to the temperature- and D-A-combination-sensitive CT interactions in the solid states. The three-dimensional weak D–A CT interactions in low-symmetry crystals induced the continuous reshaping of flat-bottomed bands into Dirac cones with decreasing temperature; this is a characteristic shape of bands that converts the behavior of SFs into that of DFs. Based on the first-principles band structures supported by the observed electronic properties, round-apex-Dirac-cone-like features appear and disappear with temperature variation. These band-structure snapshots are expected to add further detailed understanding to the related research fields.
• Integrated Computing Accelerates Design and Performance Control of New Maraging Steels

  Shixing Chen, Jingchuan Zhu, Tingyao Liu, Yong Liu, Yudong Fu, Toshihiro Shimada, Guanqi Liu

  Materials 2023年06月08日
• Interaction between diamond and alkali metals and its application to machining of diamond

  Toshihiro Shimada, Hiroki Takehana, Ichiro Yamane

  Electronics and Communications in Japan 2023年06月 

  AbstractThe interaction between diamond surfaces and alkali metals was studied experimentally and computationally. Li reacted with diamond above 600°C and significant etching of (100) surface was observed. An attempt was made to apply this etching reaction for electrical discharge machining of diamond tools.
• Detection of Water Vapor by Chemiluminescence

  島田 敏宏, Honami Nishimoto, Hikaru Hayakawa, Hisashi Ichikawa, Yoshifumi Nakacho

  Chemosensors 2023年05月09日
• Inverse Tunnel Magnetoresistance of Magnetic Tunnel Junctions with a NiCo2O4 Electrode

  Yoshinori Hara, Katsunori Yoshino, Asaka Tsujie, Toshihiro Shimada, Taro Nagahama

  AIP Advances 13 2 in press - 025162 2023年02月 [査読有り]
   

  Inverse spinel oxide NiCo₂O₄ (NCO) is known to exhibit ferrimagnetic characteristics and electrical conductivity. First-principles calculations predict NCO to be a half-metal with a negative polarization of −100%. In this study, we fabricated epitaxial NCO/MgO/Fe magnetic tunnel junctions by reactive molecular beam epitaxy and observed an inverse tunnel magnetoresistance (TMR) effect of −19.1% at 14 K, indicating that NCO has negative spin polarization. The TMR ratio monotonically decreased with increasing temperature, which was attributed to the temperature dependence of the NCO surface magnetization due to the thermal excitation of spin waves. In addition, the TMR ratio displayed strong bias voltage dependence, decreasing to less than half of the maximum value at +20 and −30 mV. These findings support the use of NCO in spintronic devices and should lead to further developments in oxide spintronics.
• Enhanced NH₃ Sensing Performance of Mo Cluster-MoS₂ Nanocomposite Thin Films via the Sulfurization of Mo₆ Cluster Iodides Precursor

  Meiqi Zhang, Fabien GRASSET, Yuji Masubuchi, 島田 敏宏, NGUYEN TK NGAN, Noée Dumait, Adèle Renaud, stéphane Cordier, David Berthebaud, Jean-François Halet, Tetsuo UCHIKOSHI

  Nanomaterials 13 3 478  2023年01月24日 [査読有り]
  
• Nearly three-dimensional Dirac fermions in an organic crystalline material unveiled by electron spin resonance

  Ryuhei Oka, Keishi Ohara, Naoya Tajima, Toshihiro Shimada, Toshio Naito

  Materials Advances 2023年 [査読有り]
   

  Original analysis methods of the electron spin resonance revealed that nearly three-dimensional Dirac fermions coexistent with standard fermions in an organic charge-transfer complex with each temperature-dependence and rotation symmetry.
• Molecular dynamics simulation of poly (ether ether ketone) (PEEK) polymer to analyze intermolecular ordering by low wavenumber Raman spectroscopy and x-ray diffraction

  Xiaoran Yang, Seiya Yokokura, Taro Nagahama, Makoto Yamaguchi, Toshihiro Shimada

  Polymers 14 24 in press - 5406 2022年12月 [査読有り][通常論文]
   

  Poly(ether ether ketone) (PEEK) is an important engineering plastic and evaluation of its local crystallinity in composites is critical for producing strong and reliable mechanical parts. Low wavenumber Raman spectroscopy and X-ray diffraction are promising techniques for the analysis of crystal ordering but a detailed understanding of the spectra has not been established. Here, we use molecular dynamics combined with a newly developed approximation to simulate local vibrational features to understand the effect of intermolecular ordering in the Raman spectra. We found that intermolecular ordering does affect the low wavenumber Raman spectra and the X-ray diffraction as observed in the experiment. Raman spectroscopy of intermolecular vibration modes is a promising technique to evaluate the local crystallinity of PEEK and other engineering plastics, and the present technique offers an estimation without requiring heavy computational resources.
• Ultrahigh pressure-induced modification of morphology and performance of MOFs-derived Cu@C electrocatalysts

  Ichiro Yamane, Kota Sato, Teruki Ando, Taijiro Tadokoro, Seiya Yokokura, Taro Nagahama, Yoshiki Kato, Tatsuya Takeguchi, Toshihiro Shimada

  Nanoscale Advances 2022年12月 [査読有り][通常論文]
   

  We report the pyrolysis of copper-containing metal-organic frameworks under high pressure and the effect of the applied pressure on the morphology and electrocatalytic performance toward the oxygen-related reactions of the...
• Synthesis of Epitaxial MoS2 / MoO2 Core-Shell Nanowires by Two-Step Chemical Vapor Deposition with Turbulent Flow and Their Physical Properties

  M. Goto, I.Yamane, S. Arasawa, T. Yanase, S. Yokokura, T. Nagahama, Yi-lun Chueh, Yongjun Shin, Yongmin Kim, T. Shimada

  ACS Omega 7 43 in press - 39369 2022年10月 [査読有り]
  
• Interaction between Diamond and Alkali Metals and its Application to Machining of Diamond

  Toshihiro Shimada, Hiroki Takehana, Ichiro Yamane

  IEEJ Transactions on Electronics, Information and Systems 142 10 1064 - 1067 2022年10月01日 [査読有り]
  
• Growth of Pentacene Crystals by Naphthalene Flux Method

  Xiaoran Yang, Mingzhe Li, Akira Maeno, Takashi Yanase, Seiya Yokokura, Taro Nagahama, Toshihiro Shimada

  ACS Omega 7 32 28618 - 28623 2022年08月16日 

  We report the crystal growth of pentacene from a solution of naphthalene. The solubility of pentacene in naphthalene was evaluated by optical absorption at elevated temperature. The crystal growth was performed in an H-shaped sealed glass tube or metal vessels sealed with ultrahigh-vacuum compatible flanges placed in heated two-zone aluminum blocks. The obtained crystals had a single-crystal-like appearance and flat surface. They were made of aligned microtwins of the "bulk type" (interlayer spacing 14.5 angstrom) polymorph.
• AQ-coupled few-layered g-C3N4 nanoplates obtained by one-step mechanochemical treatment for efficient visible-light photocatalytic H2O2 production

  Wei Liu, Run Xu, Yongye Wang, Niu Huang, Toshihiro Shimada, Liqun Ye

  International Journal of Hydrogen Energy 2022年04月
• Evaluation of crystallinity in carbon fiber‐reinforced poly(ether ether ketone) by using infrared low frequency Raman spectroscopy

  makoto yamaguchi, Shoko Kobayasi, Tomoko Numata, Nobuyuki Kamihara, Toshihiro Shimda, Mitsutoshi Jikei, Mikio Muraoka, Jonathan E. Barnsley, Sara J. Fraser‐Miller, Keith C. Gordon

  Journal of Applied Polymer Science 2022年02月20日 

  AbstractThe degree of crystallinity of poly(ether ether ketone) (PEEK) in carbon fiber reinforced composites were evaluated by using infrared low frequency Raman spectroscopy. Reference PEEK samples with varying crystallinity which are evaluated using wide‐angle X‐ray diffraction (WAXRD) were prepared. These samples were used to create a calibration curve for crystallinity using low frequency Raman spectroscopy. The WAXRD and low frequency Raman methods directly correlated. Carbon fiber reinforced PEEK samples with different cooling rates were prepared and the crystallinity was determined by using low frequency Raman spectrosopy. The crystallinity of the air‐cooled sample, water‐cooled sample, contact with metal plate and water‐cooled sample are 36%, 33%, and 17%, respectively.
• Free-Standing Nanometer-Thick Covalent Organic Framework Films for Separating CO2 and N-2

  Masaki Kato, Ryo Ota, Takashi Endo, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  ACS APPLIED NANO MATERIALS 5 2 2367 - 2374 2022年02月 

  Covalent organic frameworks (COF) have been gathering much attention because the shapes, sizes, and chemical functions of their nanostructured pores can be arbitrarily controlled by designing the organic precursors. We fabricated cm-sized free-standing COF films with the thickness of 50-100 nm by an alternating vacuum deposition polymerization method. Precise adjustment of the stoichiometry by digitally controlled deposition was essential for producing the robust free-standing COF films. High-resolution electron microscopy revealed 3 nm pore structures, which correspond to the atomic structure of the COF. Small angle X-ray diffraction shows the existence of a similar periodicity. The CO2/N-2 gas phase separation properties were evaluated from 10(3)-10(5) Pa, and the parameters for each molecular permeation were determined. Based on the detailed analysis, it was found that the selectivity comes from the greater sorption affinity of CO2 to the COF compared to N-2, which is consistent with the quantum chemical calculation. Since the vapor phase method can be used to coat various shaped templates, our method provides a new option for fabrication of neat COF membranes with various structures and their applications for the separation membrane.
• Interaction between alkali metals and diamond: Etching and charge states of NV centers

  Hiroki Takehana, Ichiro Yamane, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Carbon 182 585 - 592 2021年09月 

  Single crystal diamond particles were heated with liquid phase alkali metals (Li, Na, K) in an argon atmosphere. It was found that Li reacts with the diamond above 600 °C, Na makes the surface rougher on a nm scale at 800 °C, and K did not change the surface morphology. The etching speed by the reaction with Li is the fastest on the (001) surface. Photoluminescence of the NV- (negatively charged nitrogen-vacancy) center decreased only after the annealing with K. DFT calculations explained the strong chemical interaction between Li and the diamond (001) surfaces, and upward band bending at the interfaces with Na and K. The behavior of the NV- center photoluminescence is consistent with the extent of band bending.
• Single Crystal Growth of π-Conjugated Large Molecules without Solubilizing Alkyl Chains via the Naphthalene Flux Method

  Takashi Yanase, Hirohiko Tanoguchi, Nobuhiko Sakai, Mingoo Jin, Ichiro Yamane, Masaki Kato, Hajime Ito, Taro Nagahama, Toshihiro Shimada

  Crystal Growth & Design 21 8 4683 - 4689 2021年07月20日 [査読有り]
  
• Intersection of Organic Molecules and Carbon Materials for Sustainable Society

  Toshihiro Shimada, Wei Liu, Ichiro Yamane, Takashi Yanase

  IEEJ Transactions on Electronics, Information and Systems 141 7 761 - 766 2021年07月01日
• DFT calculation of square MoS2 nanotubes

  Meiqi Zhang, Mengting Weng, Takahiro Tamura, Manami Goto, Ichiro Yamane, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES 130 2021年06月 

  This paper present computational study on molybdenum disulfide (MoS2) nanotubes with square cross sections in order to elucidate the growth mechanism and properties of experimentally synthesized nanotubes. The results show that these square nanotubes have strain energies lower than the traditional cylinder ones in the small-diameter region. They also show a much smaller band gap and higher surface energies compared with the cylindrical ones. Zigzag and armchair chirality shows qualitatively different electronic structures about the localization of the edge states.
• Ultrahigh-Pressure Preparation and Catalytic Activity of MOF-Derived Cu Nanoparticles

  Ichiro Yamane, Kota Sato, Ryoichi Otomo, Takashi Yanase, Akira Miura, Taro Nagahama, Yuichi Kamiya, 島田 敏宏

  Nanomaterials 11 4 1040 - 1040 2021年04月 

  A metal-organic framework (MOF) consisting of Cu-benzenetricarboxylic acid was processed under ultrahigh pressure (5 GPa) and at temperature of up to 500 degrees C. The products were characterized with TEM, FTIR, and XAFS. The decomposition of the MOF started at 200 degrees C at 5 GPa. This temperature was much lower than that in the vacuum. Single-nanometer Cu nanoparticles were obtained in carbon matrix, which was significantly smaller than the Cu particles prepared at ambient pressure. The catalytic activity for Huisgen cycloaddition was examined, and the sample processed at 5 GPa showed a much improved performance compared with that of the MOF-derived Cu nanoparticles prepared without high pressure.
• Synthesis of Boron Nitride Nanotubes Using Plasma-Assisted CVD Catalyzed by Cu Nanoparticles and Oxygen

  Tatsuya Shiratori, Ichiro Yamane, Shoto Nodo, Ryo Ota, Takashi Yanase, Taro Nagahama, Yasunori Yamamoto, Toshihiro Shimada

  Nanomaterials 11 3 651 - 651 2021年03月08日 

  We found that oxidized Cu nanoparticles can catalyze the growth of boron nitride nanotubes from borazine via plasma-assisted chemical vapor deposition. The Raman spectra suggest that the formation of thin-walled nanotubes show a radial breathing mode vibration. The presence of oxygen in the plasma environment was necessary for the growth of the nanotubes, and a part of the nanotubes had a core shell structure with a cupper species inside it. In atomic resolution transmission electron microscope (TEM) images, Cu2O was found at the interface between the Cu-core and turbostratic BN-shell. The growth mechanism seemed different from that of carbon nanotube core-shell structures. Therefore, we pointed out the important role of the dynamic morphological change in the Cu2O-Cu system.
• Large Inverse Tunnel Magnetoresistance in Magnetic Tunnel Junctions with an Fe3O4 Electrode

  Shoma Yasui, Syuta Honda, Jun Okabayashi, Takashi Yanase, Toshihiro Shimada, Taro Nagahama

  PHYSICAL REVIEW APPLIED 15 3 2021年03月 

  Spinel-type magnetite Fe3O4 is predicted to be a half-metal material with negative spin polarization. However, magnetic tunnel junctions (MTJs) using an Fe3O4 electrode exhibit a small tunnel magnetoresistance (TMR) effect, the sign of which has not been established experimentally. The development of Fe3O4 as an excellent TMR material requires a better understanding of the characteristics of the interface and the phase transition of Fe3O4 called the Verwey transition. We fabricate MTJs using epitaxial Fe3O4-based stacks on MgO(001) substrates and find a large inverse TMR ratio of -55.8% at 80 K, which corresponds to 126% by the optimistic definition of the TMR ratio. The temperature dependence of the TMR ratio is significantly affected by the Verwey transition. Moreover, we investigate the dependence of TMR on oxygen partial pressure during Fe3O4 deposition. It is found that the magneto-transport properties of the MTJs show different behaviors depending on the oxygen partial pressure because the Verwey transition is sensitive to the oxygen concentration. Furthermore, the electronic and magnetic properties at the interfacial regions are investigated by x-ray magnetic spectroscopy and first-principles calculation. These findings greatly support the use of Fe3O4 in spintronic devices and should lead to further developments in oxide spintronics.
• Mechanical properties of high-crystalline diamond films grown via laser MPCVD

  Meijun Yang, Sunan Bai, Qingfang Xu, Jun Li, Toshihiro Shimada, Qizhong Li, Takashi Goto, Rong Tu, Song Zhang

  DIAMOND AND RELATED MATERIALS 109 2020年11月 

  High-crystalline diamond films were prepared by laser (wavelength: 532 nm) microwave plasma chemical vapor deposition (Laser MPCVD). The effects of laser power density (E) on the microstructure and properties of diamond films were investigated. The laser enhanced the precursor reaction process which reduces the non-diamond components such as graphite and amorphous carbon. At E = 40 W/cm(2), more methyl radicals and atomic hydrogen were generated with coupling of laser and plasma, which promoted crystal growth until the grain size reaches the maximum value of 0.72 mu m. The phase purity of film reached the highest as the full width at half maximum (FWHM) of Raman peak reached the minimum of FWHMmin = 4.2 cm(-1). And hardness (H) and Young's modulus (M) values reached the maximum of H-max = 91 GPa and M-ma(x) = 721 GPa, respectively. The discovery of the advantages of laser in diamond growth is of great significance for improving the synthesis of many technically crucial materials.
• Healing Sulfur Vacancies in Monolayer MoS2 by High-Pressure Sulfur and Selenium Annealing: Implication for High-Performance Transistors

  Takashi Yanase, Fumiya Uehara, Itsuki Naito, Taro Nagahama, Toshihiro Shimada

  ACS APPLIED NANO MATERIALS 3 10 10462 - 10469 2020年10月 

  Developing a technology to terminate chalcogen vacancies for transition-metal dichalcogenides is a crucial task for applications, such as transistors, diodes, and sensors, because chalcogen vacancies degrade the electronic and optical properties. This article reports a healing method of S vacancies in MoS2 by high-pressure annealing under a S vapor pressure of 5 atm. The crystal quality after mechanical transfer, S annealing, and vacuum annealing was systematically studied by observing the photoluminescence (PL). The remarkable recovery of the A-exciton emission peak in the PL spectrum indicated repair of the crystal quality in MoS2 by the S annealing. We also demonstrated that the S vacancies could be terminated by Se atoms using a high-pressure annealing method. The crystal quality of MoS2(1-x)Se2x alloys was confirmed by transmission electron microscopy and electron diffraction.
• NiCo2O4 films fabricated by reactive molecular beam epitaxy and annealing in various oxygen atmospheres

  Asaka Tsujie, Yoshinori Hara, Takashi Yanase, Toshihiro Shimada, Taro Nagahama

  Applied Physics Letters 116 23 232404 - 232404 2020年06月08日
• Controlling the magnetic proximity effect and anomalous Hall effect in CoFe2O4/Pt by ionic gating

  Shoto Nodo, Shimpei Ono, Takashi Yanase, Toshihiro Shimada, Taro Nagahama

  Applied Physics Express 13 6 063004 - 063004 2020年06月01日
• Post-annealed graphite carbon nitride nanoplates obtained by sugar-assisted exfoliation with improved visible-light photocatalytic performance

  Wei Liu, Takashi Yanase, Nobuhiro Iwasa, Shin Mukai, Shinichiro Iwamura, Taro Nagahama, Toshihiro Shimada

  Journal of Colloid and Interface Science 567 369 - 378 2020年05月 [査読有り][通常論文]
  
• Sugar-assisted mechanochemical exfoliation of graphitic carbon nitride for enhanced visible-light photocatalytic performance

  Wei Liu, Takashi Yanase, Nobuhiro Iwasa, Hitoshi Koizumi, Shin Mukai, Shinichiro Iwamura, Taro Nagahama, Toshihiro Shimada

  International Journal of Hydrogen Energy 45 15 8444 - 8455 2020年03月 [査読有り][通常論文]
  
• Characterization of magnetic properties of ultrathin CoFe2O4 films by utilizing magnetic proximity effect

  S. Nodo, T. Yamamoto, T. Yanase, T. Shimada, T. Nagahama

  Solid State Communications 306 113762 - 113762 2020年02月 [査読有り][通常論文]
  
• Growth Kinetics and Magnetic Property of Single-Crystal Fe Nanowires Grown via Vapor-Solid Mechanism Using Chemically Synthesized FeO Nanoparticle Catalysts

  Takashi Yanase, Uika Ogihara, Yoshihiro Awashima, Takeshi Yanagida, Kazuki Nagashima, Taro Nagahama, Toshihiro Shimada

  CRYSTAL GROWTH & DESIGN 19 12 7257 - 7263 2019年12月 [査読有り][通常論文]
   

  Single-crystal Fe nanowires (NWs) were synthesized on SiO2/Si substrates by chemical vapor deposition (CVD) using a two-flow system in the presence of FeO nanoparticles as catalysts. Transmission electron microscopy observations and an electron diffraction analysis revealed that the NW was defect-free alpha-Fe (bcc structure) oriented in the < 100 > direction. A plausible mechanism of the Fe NW growth is suggested based on the observations of the morphology and characteristic diameter of the Fe NW. We found that the NWs became polycrystalline when their diameter was approximately 100 nm. The excellent crystal quality of the single-crystal NW was confirmed by electron diffraction and the residual resistance ratio. Magnetic uniformity and a strong shape-anisotropic behavior of magnetization were observed by measuring the hysteresis loop and the angle dependence of the magneto-optical Kerr effect, respectively.
• FeOナノ粒子触媒によるMoS2ナノチューブのCVD成長と評価

  柳瀬 隆, Weng Mengting, Zhang Meiqi, 後藤真菜美, 長浜太郎, 島田 敏宏

  表面と真空 62 10 2019年10月 [査読有り][通常論文]
  
• Porous graphitic carbon nitride nanoplates obtained by a combined exfoliation strategy for enhanced visible light photocatalytic activity

  Wei Liu, Nobuhiro Iwasa, Shinichiro Fujita, Hitoshi Koizumi, Makoto Yamaguchi, Toshihiro Shimada

  Applied Surface Science 2019年09月 [査読有り][通常論文]
  
• Synthesis of Carbon Nanotubes by Plasma-Enhanced Chemical Vapor Deposition Using Fe1−xMnxO Nanoparticles as Catalysts: How Does the Catalytic Activity of Graphitization Affect the Yields and Morphology?

  Takashi Yanase, Takuya Miura, Tatsuya Shiratori, Mengting Weng, Taro Nagahama, Toshihiro Shimada

  C 5 3 46 - 46 2019年08月08日 [査読有り][通常論文]
   

  The choice of a catalyst for carbon nanotube (CNT) growth is critical to controlling the morphology and chirality of the final product. Plasma-enhanced chemical vapor deposition (PECVD) can alleviate the requirements of the catalyst, i.e., they must be active for both the decomposition of the source gas and graphitization in the conventional thermal CVD. However, it is still not well understood how the catalytic activity of the graphitization affects the yield and quality of CNTs. In this paper, we systematically investigated the influence of the catalytic activity of graphitization by tuning the composition of Fe1-xMnxO (x = 0-1) nanoparticles as catalysts. As the Mn component increased, the number of CNTs decreased because Mn has no catalytic function of the graphitization. The quality of CNTs also affected by the inclusion of the Mn component. Our study may provide useful information to develop a new catalyst for CNT growth in PECVD.
• Tunnel magnetoresistance effect in a magnetic tunnel junction with a B2-Fe3Sn electrode

  Y. Goto, T. Yanase, T. Shimada, M. Shirai, T. Nagahama

  AIP Advances 9 085322  2019年08月 [査読有り][通常論文]
  
• Study on the requirements of catalytic function for the growth of carbon nanotubes by plasma-enhanced chemical vapor deposition

  Takashi Yanase, Takuya Miura, Tatsuya Shiratori, Mengting Weng, Taro Nagahama, Toshihiro Shimada

  C: Journal of Carbon Research 5 3 46 - 46 2019年08月 [査読有り][通常論文]
  
• Synthesis of carbon-doped boron nitride nanosheets and enhancement of their room-temperature ferromagnetic properties

  Wei Liu, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Journal of Alloys and Compounds 792 1206 - 1212 2019年07月 [査読有り][通常論文]
  
• さまざまな面指数を持つcBN表面のナノインデンテーション

  田村貴大, Roman Nowak, 高倉洋礼, 島田敏宏

  New Diamond 35 3 20 - 21 2019年06月 [査読有り][通常論文]
  
• Search for new nitrogen-doped carbon materials by compressing molecular crystals

  Ichiro Yamane, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS 58 2019年04月 [査読有り][通常論文]
   

  Synthesis under high pressure is a powerful technique to obtain novel materials. We here report ultrahigh pressure experiments to search for new nitrogen-doped carbon materials. Crystalline powders of organic molecules with nitrogen atoms are used as precursors. After high pressure treatment at room temperature, precursor molecules underwent oligomerization accompanied by transformation from sp(2)-hybridization carbon atoms to sp(3) ones. (C) 2019 The Japan Society of Applied Physics
• Single crystal growth, structural analysis and electronic band structure of a nitrogen-containing polyacene BBQPP

  Nobuhiko Sakai, Takahiro Tamura, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Japanese Journal of Applied Physics 58 in press  2019年04月 [査読有り][通常論文]
  
• Single crystal growth, structural analysis and electronic band structure of a nitrogen-containing polyacene Benzo[i]benzo[6′,7′]quinoxalino[2′,3′:9,10]phenanthro[4,5-abc]phenazine

  Nobuhiko Sakai, Takahiro Tamura, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Japanese Journal of Applied Physics 58 {SB} 2019年02月 [査読有り][通常論文]
  
• Synthesis of metastable B2-type Fe–Sn alloy epitaxial films and study of their magnetic properties

  Yuki Goto, Masato Araki, Nozomi Takahashi, Takashi Yanase, Toshihiro Shimada, Masahito Tsujikawa, Masafumi Shirai, Akira Kamimaki, Satoshi Iihama, Shigemi Mizukami, Taro Nagahama

  Japanese Journal of Applied Physics 57 12 120302 - 120302 2018年10月 [査読有り][通常論文]
  
• Catalytic chemical vapor deposition and structural analysis of MoS2 nanowires

  Mengting Weng, Meiqi Zhang, Takashi Yanase, Fumiya Uehara, Taro Nagahama, Toshihiro Shimada

  Japanese Journal of Applied Physics 2018年04月 [査読有り][通常論文]
  
• Rich interfacial chemistry and properties of carbon-doped hexagonal boron nitride nanosheets revealed by electronic structure calculations

  Wei Xie, Takahiro Tamura, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Japanese Journal of Applied Physics 57 4 2018年04月01日 [査読有り][通常論文]
   

  The effect of C doping to hexagonal boron nitride (h-BN) to its electronic structure is examined by first principles calculations using the association from π-electron systems of organic molecules embedded in a two-dimensional insulator. In a monolayered carbon-doped structure, odd-number doping with carbon atoms confers metallic properties with different work functions. Various electronic interactions occur between two layers with odd-number carbon substitution. A direct sp3 covalent chemical bond is formed when C replaces adjacent B and N in different layers. A charge transfer complex between layers is found when C replaces B and N in the next-neighboring region, which results in narrower band gaps (e.g., 0.37 eV). Direct bonding between C and B atoms is found when two C atoms in different layers are at a certain distance.
• Semitransparent conductive carbon films synthesized by sintering spin-coated sp(3)-based network polymer

  Takashi Yanase, Hiroaki Uwabe, Koki Hasegawa, Taro Nagahama, Makoto Yamaguchi, Toshihiro Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS 57 3 2018年03月 [査読有り][通常論文]
   

  We synthesized semitransparent conducting thin films of amorphous carbon from sp(3)-rich network polymer. The films showed a reasonable optical transparency (58-73% transmission in the wavelength range of 380-2200 nm), a low electric resistivity (6.7 x 10(-3) Omega cm), and durability against corrosive chemical reagents. The sintering of the amorphous films results in the formation of a carbon honeycomb lattice in the films. (C) 2018 The Japan Society of Applied Physics
• Synthesis of Mo1-xNbxS2 thin films by separate-flow chemical vapor deposition with chloride sources

  Takashi Yanase, Sho Watanabe, Fumiya Uehara, Mengting Weng, Taro Nagahama, Toshihiro Shimada

  THIN SOLID FILMS 649 171 - 176 2018年03月 [査読有り][通常論文]
   

  The doping of element (Nb, Ta, etc.) into MoS2, one of the layered transition metal dichalcogenides, is a key technology for electronic devices because the lack of the p-type MoS2 has limited the range of applications. We report that the Mo1-xNbxS2 thin films were synthesized on SiO2/Si substrates by chemical vapor deposition (CVD). It was critical to use chloride sources ( MoCl5 and NbCl5) for the synthesis of Mo1-xNbxS2. The Nb concentration can be increased to 10% by controlling the supplied amount of Nb using a separate-flow CVD apparatus. The Raman spectra changed as the Nb concentration increased, appearing E-2(Nb-S) vibrational mode. The photoluminescence (PL) at 655 nm, attributed to emission from excitons, disappeared, when Nb was incorporated into the MoS2. PL due to trions at 680 nm was observed for the Mo1-xNbxS2 thin films.
• Morphology and mechanical behavior of diamond films fabricated by IH-MPCVD

  Rong Tu, Tiantian Xu, Dengfeng Li, Song Zhang, Meijun Yang, Qizhong Li, Lianmeng Zhang, Toshihiro Shimada, Takashi Goto, Ji Shi

  RSC Advances 2018年
• Fabrication of Epitaxial Fe3O4 Film on a Si(111) Substrate

  Takahashi Nozomi, Huminiuc Teodor, Yamamoto Yuta, Yanase Takashi, Shimada Toshihiro, Hirohata Atsufumi, Nagahama Taro

  Scientific reports 7 1 7009 - 7009 Nature Publishing Group 2017年12月 [査読有り][通常論文]
   

  The application of magnetic oxides in spintronics has recently attracted much attention. The epitaxial growth of magnetic oxide on Si could be the first step of new functional spintronics devices with semiconductors. However, epitaxial spinel ferrite films are generally grown on oxide substrates, not on semiconductors. To combine oxide spintronics and semiconductor technology, we fabricated Fe3O4 films through epitaxial growth on a Si(111) substrate by inserting a gamma-Al2O3 buffer layer. Both of gamma-Al2O3 and Fe3O4 layer grew epitaxially on Si and the films exhibited the magnetic and electronic properties as same as bulk. Furthermore, we also found the buffer layer dependence of crystal structure of Fe3O4 by X-ray diffraction and high-resolution transmission electron microscope. The Fe3O4 films on an amorphous-Al2O3 buffer layer grown at room temperature grew uniaxially in the (111) orientation and had a textured structure in the plane. When Fe3O4 was deposited on Si(111) directly, the poly-crystal Fe3O4 films were obtained due to SiOx on Si substrate. The epitaxial Fe3O4 layer on Si substrates enable us the integration of highly functional spintoronic devices with Si technology.
• Inverse Tunnel Magnetocapacitance in Fe/Al-oxide/Fe3O4

  Hideo Kaiju, Taro Nagahama, Shun Sasaki, Toshihiro Shimada, Osamu Kitakami, Takahiro Misawa, Masaya Fujioka, Junji Nishii, Gang Xiao

  Scientific Reports 7 1 2682  2017年12月 [査読有り][通常論文]
   

  Magnetocapacitance (MC) effect, observed in a wide range of materials and devices, such as multiferroic materials and spintronic devices, has received considerable attention due to its interesting physical properties and practical applications. A normal MC effect exhibits a higher capacitance when spins in the electrodes are parallel to each other and a lower capacitance when spins are antiparallel. Here we report an inverse tunnel magnetocapacitance (TMC) effect for the first time in Fe/AlOx/Fe3O4 magnetic tunnel junctions (MTJs). The inverse TMC reaches up to 11.4% at room temperature and the robustness of spin polarization is revealed in the bias dependence of the inverse TMC. Excellent agreement between theory and experiment is achieved for the entire applied frequency range and the wide bipolar bias regions using Debye-Frohlich model (combined with the Zhang formula and parabolic barrier approximation) and spin-dependent drift-diffusion model. Furthermore, our theoretical calculations predict that the inverse TMC effect could potentially reach 150% in MTJs with a positive and negative spin polarization of 65% and -42%, respectively. These theoretical and experimental findings provide a new insight into both static and dynamic spin-dependent transports. They will open up broader opportunities for device applications, such as magnetic logic circuits and multi-valued memory devices.
• Pinpoint-fluorinated polycyclic aromatic hydrocarbons (F-PAHs): Syntheses of difluorinated subfamily and their properties

  Kohei Fuchibe, Kento Shigeno, Nan Zhao, Hiromichi Aihara, Rikuo Akisaka, Toshiyuki Morikawa, Takeshi Fujita, Kie Yamakawa, Toshihiro Shimada, Junji Ichikawa

  JOURNAL OF FLUORINE CHEMISTRY 203 173 - 184 2017年11月 [査読有り][通常論文]
   

  Difluorinated polycyclic aromatic hydrocarbons (PAHs) containing three to five benzene rings were systematically synthesized by the Pd(II)-catalyzed Friedel-Crafts-type cyclization of 1,1,2-trifluoro- and 1,1-difluoro-1-alkenes and the In(III)-catalyzed tandem cyclization of bis(1,1-difluoroallene)s. Using an array of the di-fluorinated PAHs that were obtained and previously reported monofluorinated PAHs, the physical properties of the pinpoint-fluorinated PAHs were investigated. (i) The F-19 NMR signals of the bay-region fluorine atoms were shifted downfield by ca. 8-14 ppm for vic-difluorinated PAHs and ca. 11-19 ppm for non-vic-difludrinated and monofluorinated PAHs. (ii) The introduction of fluorine into PAH molecules increased their solubilities in organic solvents, which was best exemplified by the high solubilities of 6,7-difluoropicene (5.4 wt%) and 6-fluoropicene (5.3 wt%) in THF. (iii) The HOMO-LUMO energy gaps of the pinpoint-fluorinated PAHs were smaller than that of the corresponding fluorine-free PAH (i.e., picene) by 0.02-0.26 eV, and the HOMO and LUMO energy levels were lowered by 0.10-0.22 eV and 0.12-0.41 eV, respectively.
• Prediction of Ternary Liquidus Temperatures by Statistical Modeling of Binary and Ternary Ag-Al-Sn-Zn Systems.

  Akira Miura, Tsukasa Hokimoto, Masanori Nagao, Takashi Yanase, Toshihiro Shimada, Kiyoharu Tadanaga

  ACS omega 2 8 5271 - 5282 2017年08月31日 [査読有り][通常論文]
   

  The relationship of liquidus temperatures among six binary and four ternary phases in a Ag-Al-Sn-Zn system was analyzed by means of statistical modeling. Four statistical models to predict changes in the liquidus temperatures in Ag-Al-Sn-Zn were proposed on the basis of different hypotheses derived from macroscopic and microscopic standpoints. The results of interpolation tests to evaluate the prediction accuracies of the ternary liquidus temperatures suggested that the multivariate regression model based on binary liquidus temperatures, interactive binary liquidus temperatures, and products of atomic ratios was found to be the most effective among the four models. It was numerically shown that the prediction accuracies of the liquidus temperatures in local ternary systems of Ag-Al-Sn-Zn can be improved further by using the models identified in their neighboring systems. Finally, the possibility to extract the general trend and the abnormal combination of elements for the prediction of liquidus temperatures was discussed on the basis of the statistical framework we considered.
• Switching of the products by changing the size and shape of catalytic nanoparticles during CVD growth of MoS2 nanotubes

  Weng Mengting, Takashi Yanase, Fumiya Uehara, Sho Watanabe, Takuya Miura, Taro Nagahama, Toshihiro Shimada

  CRYSTENGCOMM 19 28 3915 - 3920 2017年07月 [査読有り][通常論文]
   

  Nanowires of layered materials are important because they exhibit the highest sensitivity as electricallydetecting chemical sensors. MoS2 nanowires have been synthesized by a catalytic chemical vapor deposition method on silicon substrates drop-coated with FeO nanoparticles of different shapes. Switching of the products (MoS2 nanowires to SiO2 nanowires) has been observed when the shapes and sizes of the FeO nanoparticles changed. MoS2 nanowires were grown in the presence of six-horned octahedral nanoparticles, whereas SiO2 nanowires were formed in the presence of spherical nanoparticles. Their morphology, crystal structure and elemental composition have been fully investigated to elucidate the growth mechanism of the nanowires. The kinetics of the grown SiO2 and MoS2 nanowires are competing, giving rise to the observed switching.
• N-2 plasma etching processes of microscopic single crystals of cubic boron nitride

  Takahiro Tamura, Takuya Takami, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS 56 6 2017年06月 [査読有り][通常論文]
   

  We studied the N-2 plasma etching of cubic boron nitride (cBN). We have developed experimental techniques for handling 200-mu m-size single crystals for the preparation of surfaces with arbitrary crystal indexes, plasma processes, and surface analyses. We successfully prepared smooth surfaces of cBN with roughness smaller than 10 nm and found that the etching behavior was strongly influenced by the surface indexes. The morphology of the etched surfaces can be explained by the chemical stability of (111)B surfaces. (C) 2017 The Japan Society of Applied Physics
• The magnetic properties of Fe3O4/nonmagnetic metal/Fe hybrid systems

  K. Omori, T. Kawai, N. Takahashi, T. Yanase, T. Shimada, T. Nagahama

  Applied Physics Letters 110 21 212402 - 212402 2017年05月22日 [査読有り][通常論文]
   

  Fe3O4 possesses unique properties such as high Curie temperature and half-metallic nature and therefore can function as a high-spin-polarized electrode in spintronic devices. In order to use this compound in such devices, the magnetic characteristics of multilayers used in these devices, which include Fe3O4, should be highly controllable. In this study, we fabricated Fe3O4/Pt or Cr (0-10 nm)/Fe systems through epitaxial growth on MgO(110) substrates in order to investigate the magnetic coupling in Fe3O4 and metallic hybrid systems. We found that these two systems show a marked difference in the dependence of the coercive field (H-c) of the Fe layer on the nonmagneticmetal- layer thickness. Hc for the system with Pt showed variation characteristics of interlayer exchange coupling in metal systems, while H-c increased monotonically with the thickness of the Cr layer. Published by AIP Publishing.
• A thermocouple-based remote temperature controller of an electrically-floated sample for plasma CVD of nanocarbons with bias voltage

  Toshihiro Shimada, Takuya Miura, Wei Xie, Takashi Yanase, Taro Nagahama

  MEASUREMENT 102 244 - 248 2017年05月 [査読有り][通常論文]
   

  We report an accurate and easy-to operate instrument for the temperature control of an electrically floated sample using a thermocouple in direct contact with it. The signal was transmitted via 2.45 GHz WiFi. We measured and analyzed the discrepancy between the thermocouple and a radiation thermometer for the plasma CVD of carbon nanomaterials under sample bias. A successful protection method from abnormal discharge in the plasma is also provided. (C) 2017 Elsevier Ltd. All rights reserved.
• Inverse Tunnel Magnetocapacitance in Fe/Al-oxide/Fe3O4

  Hideo Kaiju, Taro Nagahama, Shun Sasaki, Toshihiro Shimada, Osamu Kitakami, Takahiro Misawa, Masaya Fujioka, Junji Nishii, Gang Xiao

  Scientific Reports 7 2682 - 2682 2017年03月 [査読有り][通常論文]
  
• N2 plasma etching processes of microscopic single crystals of cubic boron nitride

  Takahiro Tamura, Takuya Takami, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Jpn. J. Appl. Phys. 56 06HF01  2017年03月 [査読有り][通常論文]
  
• 真空封止・試料固定用の接着技術

  島田敏宏, 柳瀬隆, 田村貴大, 高見拓哉, 伊髙健治

  表面科学 38 2017年02月 [査読有り][招待有り]
  
• Amorphous organic superlattices

  Takashi Yanase, Toshihiro Shimada

  Horizons in World Physics 291 117 - 128 2017年01月01日 

  In this chapter, we describe the fabrication and functions of organic superlattices. Amorphous superlattices are easy to fabricate and can be produced vert rapidly because there is no restriction of epitaxial relations. However, ordinary semiconductor materials do not function electronically because of the charge traps abundant in amorphous state. Organic semiconductors are rare exception of this problem because they can function well in the amorphous form, for example, in organic light emitting diodes. We demonstrated the useful function of amorphous organic superlattices by making "tricolor" superlattices with p-type, ntype and piezoelectric layers. We confirmed that the superlattice showed photoresponsive mechanical motion.
• Switching of the products by changing the size and shape of catalytic nanoparticles during CVD growth of MoS2 nanotubes

  Weng Mengting, Takashi Yanase, Fumiya Uehara, Sho Watanabe, Takuya Miura, Taro Nagahama, Toshihiro Shimada

  CrystEngComm 19 28 3915 - 3920 2017年 [査読有り][通常論文]
   

  Nanowires of layered materials are important because they exhibit the highest sensitivity as electricallydetecting chemical sensors. MoS2 nanowires have been synthesized by a catalytic chemical vapor deposition method on silicon substrates drop-coated with FeO nanoparticles of different shapes. Switching of the products (MoS2 nanowires to SiO2 nanowires) has been observed when the shapes and sizes of the FeO nanoparticles changed. MoS2 nanowires were grown in the presence of six-horned octahedral nanoparticles, whereas SiO2 nanowires were formed in the presence of spherical nanoparticles. Their morphology, crystal structure and elemental composition have been fully investigated to elucidate the growth mechanism of the nanowires. The kinetics of the grown SiO2 and MoS2 nanowires are competing, giving rise to the observed switching.
• Accurate and stable equal-pressure measurements of water vapor transmission rate reaching the 10−6 g m−2 day−1 range

  Y. Nakano, T. Yanase, T. Nagahama, H. Yoshida, T. Shimada

  Scientific Reports 6 35408  2016年10月 [査読有り][通常論文]
   

  The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10(-6) g m(-2) day(-1) that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element.
• Formation of bismuth-core-carbon-shell nanoparticles by bismuth immersion during plasma CVD synthesis of thin diamond films

  Takahiro Tamura, Takuya Takami, Sachio Kobayashi, Taro Nagahama, Takashi Yanase, Toshihiro Shimada

  Diamond and Related Materials 69 127 - 132 2016年10月 [査読有り][通常論文]
   

  This paper describes an attempt to synthesize bismuth-doped diamond by plasma CVD. Solid bismuth was inserted into the reaction plasma of CH4 and H-2. Examination by TEM showed that most of the bismuth was included as Bi nanoparticles in the carbon nanospheres, which segregated at the grain boundary of the diamond polycrystals. Diffraction peaks corresponding to the carbon allotrope Chaoite were observed at the grain boundaries. The Raman spectra showed very complex features between 100-1600 cm(-1), suggesting the existance of molecule-like species. (C) 2016 Elsevier B.V. All rights reserved.
• Chemical Vapor Deposition of NbS2 from a Chloride Source with H-2 Flow: Orientation Control of Ultrathin Crystals Directly Grown on SiO2/Si Substrate and Charge Density Wave Transition

  Takashi Yanase, Sho Watanabe, Mengting Weng, Makoto Wakeshima, Yukio Hinatsu, Taro Nagahama, Toshihiro Shimada

  CRYSTAL GROWTH & DESIGN 16 8 4467 - 4472 2016年08月 [査読有り][通常論文]
   

  This article reports the growth and characterization of z-axis-oriented NbS2 thin films on SiO2/Si substrate by ambient pressure chemical vapor deposition (CVD) using a generic metal chloride source. We found that NbS2 nanosheets can be grown directly on the SiO2/Si substrate with the aid of hydrogen gas mixed in the carrier gas. Detailed examination Of the growth parameters was made possible using a separate-flow CVD apparatus. It appears that the major cause of the misorientation is the off-stoichiometry with surplus Nb. The quality of the films was evaluated by X-ray diffraction and Raman spectroscopy as well as resistivity measurements at low temperatures. They showed a resistivity minimum at the same temperature of the charge density wave (CDW) transition for a bulk single crystal of 3R-NbS2.
• Chemical Vapor Deposition of MoS2: Insight Into the Growth Mechanism by Separated Gas Flow Experiments

  Takashi Yanase, Sho Watanabe, Mengting Weng, Taro Nagahama, Toshihiro Shimada

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 16 4 3223 - 3227 2016年04月 [査読有り][通常論文]
   

  We report detailed experiments on chemical vapor deposition of an atomic layer semiconductor MoS2. We developed a new type of CVD system in which MoO3 and S sources are separately supplied to the substrates. It has become possible to precisely control the supply of the materials separately in the order of seconds. Raman and XPS analysis of the films grown under various conditions revealed that the initially obtained films are S-deficient and complete stoichiometry is reached after several minutes under S vapor flow.
• Carbon-Doped Hexagonal Boron Nitride: Analysis as π-Conjugate Molecules Embedded in Two Dimensional Insulator

  島田敏宏

  C: Journal of Carbon Research 2, 2(2016); doi:10.3390/c2010002 2 1 2 - 2 MDPI 2016年01月29日 [査読有り][通常論文]
   

  We analyzed the electronic structures of carbon-doped hexagonal boron nitride, focusing on the comparison with the corresponding π-conjugate hydrocarbon molecules and odd-number substitution by first principle calculation. The band gaps are about the half that of the HOMO-LUMO gaps of corresponding hydrocarbons, except for the cis-butadiene structure in which aromatic hexagonal ring formation is important. Odd number doping makes metallic materials with very different work functions, depending upon the difference in B and N numbers, and has an expected application as electrodes for flexible devices.
• Thin film growth of MOS2

  Takashi Yanase, Toshihiro Shimada

  Molybdenum Disulfide: Synthesis, Properties and Industrial Applications 1 - 20 2016年01月01日 

  This chapter describes thin film growth to synthesize nanosheets (few- or mono- layer) of molybdenum disulfide (MoS2), mainly focusing on chemical vapor deposition (CVD). The CVD system is still being improved in terms of the controllability and reproducibility: from one zone systems, two zone systems, three zone systems to finally two flow systems. The growth conditions of CVD and the surface treatment of the substrate are critically reviewed. The appearance of MoS2 nanosheets on substrates shows various shapes such as star shape, dendritic shape, and round shape due to kinetic effects and off-stoichiometric growth conditions. The mechanism of the shape evolution is explained in this chapter. Impurity-assisted method is recently proposed to enlarge grain size and to lower growth temperature. Methods to evaluate the MoS2 nanosheets synthesized by CVD are also discussed. The crystallinity strongly affects the device performance. Fabrication of heterostructures including MoS2 is now strenuously studied as a fundamental semiconductor technology.
• Investigation of epitaxial growth and tunnel magnetoresistance effects in magnetic tunnel junctions including spinel ferrite layers

  Nozomi Takahashi, Tomohiro Kawai, Takashi Yanase, Toshihiro Shimada, Taro Nagahama

  JAPANESE JOURNAL OF APPLIED PHYSICS 54 11 118003  2015年11月 [査読有り][通常論文]
   

  The combination of magnetic tunnel junctions (MTJs) and magnetic insulating (MI) layers has attracted much attention because of its potential as novel spintronic devices. To realize such devices, the epitaxial growth and magnetoresistance of MTJs with spinel ferrite were investigated. Nonmagnetic (NM) layers were inserted between the MTJs and MI layers as magnetic decoupling layers, the epitaxial growth of which was important to obtain high-quality epitaxial multilayers. Multilayers of MTJ/NM/MI and MI/NM/MTJ were fabricated and tunnel magnetoresistance (TMR) values of 70 and 50% at room temperature, respectively, were observed. The shape of the magnetoresistance curve depended on the sample structure. (C) 2015 The Japan Society of Applied Physics
• Colorful Carbon Nanopopcorns Formed by Codepositing C-60 with Diamond-like Carbon Followed by Reaction with Water Vapor

  Wei Xie, Aiko Kawahito, Takuya Miura, Takashi Endo, Yongming Wang, Takashi Yanase, Taro Nagahama, Yukitoshi Otani, Toshihiro Shimada

  CHEMISTRY LETTERS 44 9 1205 - 1207 2015年09月 [査読有り][通常論文]
   

  We report the synthesis of a new carbon material diamondlike carbon film codeposited with 1% C-60 molecules by plasma-assisted chemical vapor deposition. The synthesized films exhibited strong iridescent colors after being exposed to an atmosphere containing water vapor. An electron microscopy examination revealed that the film expanded by a factor of more than two, while forming 10-100-nm-sized grain-like structures after its exposure to water vapor. This work demonstrates a new concept of incorporating reaction centers in carbon solids to make carbon-based nanostructures.
• Stable measurement of 10-6 gm-2day-1 water vapor transmission rate in barrier materials by intermittent accumulation and release by a cold trap

  Yoichiro Nakano, Yoshikazu Takahashi, Toshiyuki Kanno, Hajime Yoshida, Toshihiro Shimada

  Digest of Technical Papers - SID International Symposium 46 3 1639 - 1642 2015年06月01日 

  We report an ultrasensitive and stable instrument for water vapor transmission rate evaluation. Water vapor permeated through gas barrier is condensed by a cold trap and measured by a mass spectrometer. Intermittent absorption and release operation of the cold trap enables the measurement immune to gradual change of background HjO.
• あ

  A. Kawahito, T. Endo, T. Yanase, T. Nagahama, T. Shimada

  J. Appl. Phys. in press 17 17D506 - 17D506 2015年05月07日 [査読無し][通常論文]
  
• フレキシブルデバイスのための 価数変化可能な極板を持つ蓄電素子の静電気学的考察

  島田敏宏, 柳瀬隆, 長浜太郎

  電気学会論文C部門誌 135 2 164 - 167 2015年02月01日 [査読無し][通常論文]
   

  Charge storage devices in the film-base flexible electronics are very important for the application of those devices in daily life. In order to examine the recently reported solid state capacitor with ionizable charge traps, we present an analysis of an electrostatic model. It shows a charge-voltage characteristic resembling a chemical battery. While the energy density per charge is great in these devices, the energy density of the capacitor with ionizable traps will be lower than that of an ordinary capacitor with metal electrodes, assuming the same withstanding voltage and the same geometry.
• Multilayered MoS2 nanoflakes bound to carbon nanotubes as electron acceptors in bulk heterojunction inverted organic solar cells

  Jeon, Il, Kutsuzawa, Dai, Hashimoto, Yu, Yanase, Takashi, Nagahama, Taro, Shimada, Toshihiro, Matsuo, Yutaka

  Organic Electronics 17 275 - 280 2015年 [査読有り][通常論文]
   

  We demonstrate the deposition of multilayered MoS2 on a low-cost metallic-semiconducting carbon nanotube via chemical vapor deposition, and the use of this material as electron acceptor species forming a bulk heterojunction with P3HT in inverted-type organic photovoltaics (OPVs). This is an uplifting discovery, in which MoS2 has been used as an electron acceptor in spite of its innate immiscibility with organic compounds. This is possible because we utilize carbon nanotube's nature to intercalate with P3HT through pi-pi interaction. The successful binding of MoS2 onto carbon nanotube bundles and its optoelectronic effect as a photovoltaic device has been lucidly analyzed through various techniques in this paper. The effect has been ultimately evidenced by a power conversion efficiency of 0.46%, which proves MoS2 with many advantages can also be used as a photoactive layer. (C) 2014 Elsevier B.V. All rights reserved.
• フレキシブルデバイスのための 価数変化可能な極板を持つ蓄電素子の静電気学的考察

  島田敏宏, 柳瀬隆, 長浜太郎

  電気学会論文C部門誌 135 2 164 - 167 2015年 [査読有り][通常論文]
   

  Charge storage devices in the film-base flexible electronics are very important for the application of those devices in daily life. In order to examine the recently reported solid state capacitor with ionizable charge traps, we present an analysis of an electrostatic model. It shows a charge-voltage characteristic resembling a chemical battery. While the energy density per charge is great in these devices, the energy density of the capacitor with ionizable traps will be lower than that of an ordinary capacitor with metal electrodes, assuming the same withstanding voltage and the same geometry.
• 逐次蒸着した有機半導体pn接合における自発的な分子の混合

  島田敏宏, 柳瀬隆, 長浜太郎, 土田裕也, 村谷直紀

  電気学会論文C部門誌 135 2 160 - 163 2015年 [査読有り][通常論文]
   

  Frontier Chemistry Center, Hokkaido University Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan Graduate School of Chemical Sciences and Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan Flexible solar cells made of organic semiconductors are promising for the application to the photovoltaic energy sources for flexible devices and those can be attached to any curved surfaces. Mixing and phase separation of different molecules are important for the formation of bulk-hetero junctions. We found that DNTT (dinaphtotienothiophene) and C60 spontaneously mixes when they are sequentially deposited. The driving force does not seem to be the charge transfer between p-type and n-type molecules but the maximization of van der Waals attraction coming from the molecular shapes.
• Fabrication of Fe nanowires on yittrium-stabilized zirconia single crystal substrates by thermal CVD methods

  Kawahito, A, Yanase, T, Endo, T, Nagahama, T, Shimada, T

  Journal of Applied Physics 117 17 17D506/1 - 17D506/4 2015年 [査読有り][通常論文]
   

  Magnetic nanowires (NWs) are promising as material for use in spintronics and as the precursor of permanent magnets because they have unique properties due to their high aspect ratio. The growth of magnetic Fe whiskers was reported in the 1960s, but the diameter was not on a nanoscale level and the growth mechanism was not fully elucidated. In the present paper, we report the almost vertical growth of Fe NWs on a single crystal yttrium-stabilized zirconia (Y0.15Zr0.85O2) by a thermal CVD method. The NWs show a characteristic taper part on the bottom growing from a trigonal pyramidal nucleus. The taper angle and length can be controlled by changing the growth condition in two steps, which will lead to obtaining uniformly distributed thin Fe NWs for applications. (C) 2015 AIP Publishing LLC.
• 逐次蒸着した有機半導体pn接合における自発的な分子の混合

  島田敏宏, 柳瀬隆, 長浜太郎, 土田裕也, 村谷直紀

  電気学会論文C部門誌 135 2 160 - 163 2015年 [査読無し][通常論文]
   

  Frontier Chemistry Center, Hokkaido University Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan Graduate School of Chemical Sciences and Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan Flexible solar cells made of organic semiconductors are promising for the application to the photovoltaic energy sources for flexible devices and those can be attached to any curved surfaces. Mixing and phase separation of different molecules are important for the formation of bulk-hetero junctions. We found that DNTT (dinaphtotienothiophene) and C60 spontaneously mixes when they are sequentially deposited. The driving force does not seem to be the charge transfer between p-type and n-type molecules but the maximization of van der Waals attraction coming from the molecular shapes.
• Versatile Simple Doping Technique for Diamond by Solid Dopant Source Immersion during Microwave Plasma CVD

  Takahiro Tamura, Takashi Yanase, Taro Nagahama, Makoto Wakeshima, Yukio Hinatsu, Toshihiro Shimada

  CHEMISTRY LETTERS 43 10 1569 - 1571 2014年10月 [査読無し][通常論文]
   

  We demonstrate a new doping technique for chemical vapor deposition (CVD) growth of diamond. The method involves immersing a solid-state dopant source into the plasma during microwave plasma-assisted CVD. We applied this simple and versatile technique to the growth of boron-doped diamond. The grown films were characterized by X-ray diffraction (XRD), Raman microscopy, glow discharge optical emission spectroscopy (GDOES), and electrical conductivity measurements. The average concentration of boron was 0.5 atom % and the conductivity was 1.5 x 10(-2) Omega cm, which showed irregular behavior at low temperature.
• Magnetic properties of epitaxial Fe3O4 films with various crystal orientations and tunnel magnetoresistance effect at room temperature

  Taro Nagahama, Yuya Matsuda, Kazuya Tate, Tomohiro Kawai, Nozomi Takahashi, Shungo Hiratani, Yusuke Watanabe, Takashi Yanase, Toshihiro Shimada

  APPLIED PHYSICS LETTERS 105 10 102410  2014年09月 [査読無し][通常論文]
   

  Fe3O4 is a ferrimagnetic spinel ferrite that exhibits electric conductivity at room temperature (RT). Although the material has been predicted to be a half metal according to ab-initio calculations, magnetic tunnel junctions (MTJs) with Fe3O4 electrodes have demonstrated a small tunnel magnetoresistance (TMR) effect. Not even the sign of the tunnel magnetoresistance ratio has been experimentally established. Here, we report on the magnetic properties of epitaxial Fe3O4 films with various crystal orientations. The films exhibited apparent crystal orientation dependence on hysteresis curves. In particular, Fe3O4(110) films exhibited in-plane uniaxial magnetic anisotropy. With respect to the squareness of hysteresis, Fe3O4 (111) demonstrated the largest squareness. Furthermore, we fabricated MTJs with Fe3O4(110) electrodes and obtained a TMR effect of -12% at RT. The negative TMR ratio corresponded to the negative spin polarization of Fe3O4 predicted from band calculations. (C) 2014 AIP Publishing LLC.
• Electrostatic model of solid-state capacitor with ionizable charge traps

  Toshihiro Shimada, Taro Nagahama, Takashi Yanase

  JAPANESE JOURNAL OF APPLIED PHYSICS 53 8 88004  2014年08月 [査読無し][通常論文]
   

  We present the analysis of a simple electrostatic model of a solid-state capacitor with ionizable charge traps. It shows a charge voltage characteristic resembling a chemical battery. With a given withstanding voltage and the same geometry, the energy density of the capacitor with ionizable traps will be lower than that of an ordinary capacitor with metal electrodes. (C) 2014 The Japan Society of Applied Physics
• Formation of graphite zigzag edges by cathodic electrochemical etching in acidic solution

  Toshihiro Shimada, Shosei Kubota, Takashi Yanase, Taro Nagahama

  CARBON 67 300 - 303 2014年02月 [査読無し][通常論文]
   

  We examined the edge structure of graphite formed by a cathodic electrochemical reaction in acid solutions associated with water electrolysis. Pole figures of the X-ray diffraction show that the edge orientation is parallel to the zigzag edge direction on a macroscopic scale. The polarization dependence of the G-band and D-band of the Raman spectra is consistent with the zigzag edge formation on a microscopic scale. It was found that the etched carbon atoms are converted to CH4 in the evolving gas and molecular species in the solution. (C) 2013 Elsevier Ltd. All rights reserved.
• Diamond-like carbon doped with highly π -conjugate molecules by plasma-assisted CVD

  Wei Xie, Naoki Muraya, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  Jpn. J. Appl. Phys. 53 1 10203  2014年01月 [査読有り][通常論文]
   

  We demonstrate the synthesis of diamond-like carbon (DLC) doped with highly pi-conjugated molecules by codepositing organic semiconductor molecules during the plasma-assisted chemical vapor deposition of DLC. From the results of optical absorption spectroscopy, it was revealed that organic semiconductor molecules reacted with plasma but were not completely decomposed. The results of Raman spectroscopy strongly suggested that a certain chemical moiety remained in the film. (C) 2014 The Japan Society of Applied Physics
• Fe whisker growth revisited: effect of Au catalysis for [02(1) over bar] oriented nanowires with 100 nm diameter

  T. Yanase, A. Kawahito, Y. Hashimoto, T. Endo, Y. Wang, T. Nagahama, T. Shimada

  RSC ADVANCES 4 52 27620 - 27624 2014年 [査読無し][通常論文]
   

  We re-examined the growth of single crystalline Fe whiskers by chemical vapour deposition with regard to modern nanowire (NW) growth techniques. Single Fe NWs (100-300 nm diameter) with a high aspect ratio and unique [021] orientation were grown by optimizing the flow of raw materials (FeCl2 and H-2) and using a Au nanoparticle catalyst and single crystalline substrate. The growth mechanism was investigated by transmission electron microscopy and electron diffraction analysis of the NW-catalyst interface.
• Fabrication and characterization of photo-responsive organic p-type/n-type/piezoelectric tricolor superlattices

  Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  APPLIED PHYSICS LETTERS 103 13 133305  2013年09月 [査読無し][通常論文]
   

  In order to combine the photovoltaic and piezoelectric activities in a single film, we fabricated tricolor superlattices consisting of an organic p-n junction and a piezoelectric polymer with sub-nm thickness control. The photovoltaic response of each repeating unit was saturated at 10 nm each as a function of the layer thicknesses. The capacitance across the 50 periods of superlattice changed by 0.009 pF upon photo-irradiation, which corresponds to a 2 nm thickness change of a 1-mu m thick film. The characteristic time dependent behaviors of the capacitance of the superlattice consist of photocarrier generation, electrostriction, and poling of the piezoelectric polymer. (C) 2013 AIP Publishing LLC.
• In-Plane Orientation Control of 2,7-Diphenyl[1]benzothieno[3,2-b][1]benzothiophene Monolayer on Bismuth-Terminated Si(111) Vicinal Surfaces with Wettability Optimization

  Manabu Ohtomo, Yuya Tsuchida, Naoki Muraya, Takashi Yanase, Seiji Sakai, Tetsu Yonezawa, Taro Nagahama, Tetsuya Hasegawa, Toshihiro Shimada

  JOURNAL OF PHYSICAL CHEMISTRY C 117 22 11555 - 11561 2013年06月 [査読有り][通常論文]
   

  We report the in-plane orientation control of a high-mobility organic semiconductor: 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT). As previously reported for the monolayer pentacene, it was revealed that bunched steps on the vicinal Si(111) with a bismuth termination break the surface 3-fold symmetry and reduce the multiple orientation of the DPh-BTBT grains into a quasi-single orientation. Interestingly, the critical step height necessary for the orientation control was higher than that of pentacene. We examined several mechanisms of orientation control and concluded that the facet nanostructure fabricated by step bunching works as an anisotropic template for the nucleation. We also show the wettability optimization of the bismuth-terminated silicon surface and show that the growth mode of DPh-BTBT is dependent on the surface nanostructure of Bi-Si.
• In-Plane Orientation Control of 2,7-Diphenyl[1]benzothieno[3,2-b][1]benzothiophene Monolayer on Bismuth-Terminated Si(111) Vicinal Surfaces with Wettability Optimization

  Manabu Ohtomo, Yuya Tsuchida, Naoki Muraya, Takashi Yanase, Seiji Sakai, Tetsu Yonezawa, Taro Nagahama, Tetsuya Hasegawa, Toshihiro Shimada

  JOURNAL OF PHYSICAL CHEMISTRY C 117 22 11555 - 11561 2013年06月 [査読有り][通常論文]
   

  We report the in-plane orientation control of a high-mobility organic semiconductor: 2,7-diphenyl[1]benzothieno[3,2-b][1]benzothiophene (DPh-BTBT). As previously reported for the monolayer pentacene, it was revealed that bunched steps on the vicinal Si(111) with a bismuth termination break the surface 3-fold symmetry and reduce the multiple orientation of the DPh-BTBT grains into a quasi-single orientation. Interestingly, the critical step height necessary for the orientation control was higher than that of pentacene. We examined several mechanisms of orientation control and concluded that the facet nanostructure fabricated by step bunching works as an anisotropic template for the nucleation. We also show the wettability optimization of the bismuth-terminated silicon surface and show that the growth mode of DPh-BTBT is dependent on the surface nanostructure of Bi-Si.
• Estimation of Gas Permeation Characteristics of Ultrahigh Barrier Edge Sealing Materials from Asymptotic Solution of Diffusion Equation

  Toshihiro Shimada, Takashi Yanase, Taro Nagahama, Toshiyuki Kanno

  JAPANESE JOURNAL OF APPLIED PHYSICS 52 5 2013年05月 [査読有り][通常論文]
   

  Materials and structures for water vapor barrier sealing are now actively studied, as the commercialization of organic electronic devices has become a reality. In this paper, we focus on the edge sealing barriers, in which diffusion plays an essential role. In the past, the diffusion-limited gas barrier properties were analyzed in the steady-state approximation, which is never reached within the device lifetime in the application for organic electronics. We analyze them using a simple analytical model. The diffusion before reaching the steady state is a strongly non-linear process, as is well known, and the length scale of approximately 1-10mm is very important when a practical polymer resin is used for the edge seal. (C) 2013 The Japan Society of Applied Physics
• X-ray absorption and magnetic circular dichroism characterization of Fe-doped TiO2-delta thin films

  Sakai, E, Amemiya, K, Chikamatsu, A, Hirose, Y, Shimada, T, Hasegawa, T

  Journal of Magnetism and Magnetic Materials 333 130 - 133 2013年05月 [査読有り][通常論文]
  
• Estimation of Gas Permeation Characteristics of Ultrahigh Barrier Edge Sealing Materials from Asymptotic Solution of Diffusion Equation

  Toshihiro Shimada, Takashi Yanase, Taro Nagahama, Toshiyuki Kanno

  JAPANESE JOURNAL OF APPLIED PHYSICS 52 5 05DA12  2013年05月 [査読無し][通常論文]
   

  Materials and structures for water vapor barrier sealing are now actively studied, as the commercialization of organic electronic devices has become a reality. In this paper, we focus on the edge sealing barriers, in which diffusion plays an essential role. In the past, the diffusion-limited gas barrier properties were analyzed in the steady-state approximation, which is never reached within the device lifetime in the application for organic electronics. We analyze them using a simple analytical model. The diffusion before reaching the steady state is a strongly non-linear process, as is well known, and the length scale of approximately 1-10mm is very important when a practical polymer resin is used for the edge seal. (C) 2013 The Japan Society of Applied Physics
• Cobalt epitaxial nanoparticles on CaF2/Si(111): Growth process, morphology, crystal structure, and magnetic properties

  N. S. Sokolov, S. M. Suturin, B. B. Krichevtsov, V. G. Dubrovskii, S. V. Gastev, N. V. Sibirev, D. A. Baranov, V. V. Fedorov, A. A. Sitnikova, A. V. Nashchekin, V. I. Sakharov, I. T. Serenkov, T. Shimada, T. Yanase, M. Tabuchi

  Physical Review B - Condensed Matter and Materials Physics 87 12 2013年03月07日 [査読有り][通常論文]
   

  We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of Co nanoislands on CaF2/Si(111) surface. In order to have a full appreciation of complex growth kinetics at different stages, a comprehensive study of Co growth on CaF2 is carried out by atomic force, scanning electron, and transmission electron microscopies in the direct space, as well as by x-ray and electron diffraction in the reciprocal space. These experimental data are complemented by theoretical modeling. Magnetic properties are characterized by magneto-optical Kerr effect and superconducting quantum interference device magnetometries. Key effects influencing the Co growth on fluorite are addressed, including the sticking probability, the preferential nucleation sites, the size and shape time evolution, the dependence of Co morphology on temperature and Co exposure, and the coalescence mechanism. The two-stage deposition technique is developed, whereby the low-temperature seeding stage is used to facilitate Co nucleation, and the follow-up high-temperature deposition yields Co particles with high crystalline quality. Our results enable precise control over the resulting morphology, spatial ordering, and crystal structure affecting the magnetic properties. In particular, it is demonstrated that the transformation from dense to isolated Co nanoparticles leads to the change of the in-plane and out-of-plane magnetic anisotropy and also the sign of polar and longitudinal magneto-optical Kerr effects. © 2013 American Physical Society.
• Cobalt epitaxial nanoparticles on CaF2/Si(111): Growth process, morphology, crystal structure, and magnetic properties

  N. S. Sokolov, S. M. Suturin, B. B. Krichevtsov, V. G. Dubrovskii, S. V. Gastev, N. V. Sibirev, D. A. Baranov, V. V. Fedorov, A. A. Sitnikova, V. Nashchekin, V. I. Sakharov, I. T. Serenkov, T. Shimada, T. Yanase, M. Tabuchi

  PHYSICAL REVIEW B 87 12 125407  2013年03月 [査読無し][通常論文]
   

  We study molecular beam epitaxy growth, morphology, crystal structure, and magnetic properties of Co nanoislands on CaF2/Si(111) surface. In order to have a full appreciation of complex growth kinetics at different stages, a comprehensive study of Co growth on CaF2 is carried out by atomic force, scanning electron, and transmission electron microscopies in the direct space, as well as by x-ray and electron diffraction in the reciprocal space. These experimental data are complemented by theoretical modeling. Magnetic properties are characterized by magneto-optical Kerr effect and superconducting quantum interference device magnetometries. Key effects influencing the Co growth on fluorite are addressed, including the sticking probability, the preferential nucleation sites, the size and shape time evolution, the dependence of Co morphology on temperature and Co exposure, and the coalescence mechanism. The two-stage deposition technique is developed, whereby the low-temperature seeding stage is used to facilitate Co nucleation, and the follow-up high-temperature deposition yields Co particles with high crystalline quality. Our results enable precise control over the resulting morphology, spatial ordering, and crystal structure affecting the magnetic properties. In particular, it is demonstrated that the transformation from dense to isolated Co nanoparticles leads to the change of the in-plane and out-of-plane magnetic anisotropy and also the sign of polar and longitudinal magneto-optical Kerr effects. DOI: 10.1103/PhysRevB.87.125407
• Influence of molecular structure on plasma carbonization of organic semiconductor molecules

  Toshihiro Shimada, Naoki Muraya, Jun Tomita, Takashi Yanase, Taro Nagahama

  Journal of Physics: Conference Series 441 1 12041  2013年 [査読無し][通常論文]
   

  The plasma treatment of organic semiconductor molecules includes issues related with nanoscale plasma interfaces. The process was examined by optical emission spectroscopy. It was found that molecules are sublimed by the heat and decomposed by the interaction with the plasma. The product carbon solids were examined by Raman spectroscopy. The raman spectra are strongly dependent on the molecular structures. The carbon solids which does not show graphitic Raman spectra have nanostructures originating from initial molecules.
• Fabrication of ZnO Nanorods by Atmospheric-Pressure Solid-Source CVD Using Ethanol-Assisted Low-Temperature Vaporization

  Sawako Miyamoto, Tetsuya Hasegawa, Hiroyuki Takahashi, Tetsu Yonezawa, Hajime Kiyono, Takashi Yanase, Taro Nagahama, Toshihiro Shimada

  BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 85 12 1287 - 1292 2012年12月 [査読有り][通常論文]
   

  We report a method to produce vapor species from ZnO powder for the fabrication of ZnO nanorods. Mixing ethanol vapor with the inert carrier gas substantially lowered the gasification temperature of ZnO. c Axis-aligned ZnO nanorods were obtained by dispersing gold nanoparticles on Si substrates. The growth was identified as a vapor-solid (VS) mechanism. Choice of the substrate materials and their surface morphology were both critically important to control the shapes and orientation of grown ZnO.
• Solvent Effects on the Transient Characteristics of Liquid-Gate Field Effect Transistors with Silicon Substrate

  Takashi Yanase, Tetsuya Hasegawa, Taro Nagahama, Toshihiro Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS 51 11 111803  2012年11月 [査読有り][通常論文]
   

  The transient characteristics of electric double layer (EDL) gated field-effect transistors with Si as an active semiconductor were studied using various electrolyte solutions of LiBF4 by applying a step-function voltage to determine the optimum electrolyte for semiconductor circuits using EDLs. The t(R), determined by EDL dynamics in the present experiment, was minimum as a function of the kind of solvent used owing to the competing effects of the EDL thickness and viscosity. The responses of the electrolyte solutions with various solvents at the same concentration were classified into three categories on the basis of t(R): slow response of a complex-forming solvent, intermediate response of protic solvents, and fast response of nonprotic solvents. The best response time was 55 mu s when a 1.0M acetonitrile solution was used as the liquid-gate insulator. (C) 2012 The Japan Society of Applied Physics
• Oxygen-17 nuclear magnetic resonance measurements on apatite-type lanthanum silicate (La-9.33(SiO4)(6)O-2)

  Hajime Kiyono, Yuuya Matsuda, Toshihiro Shimada, Mariko Ando, Itaru Oikawa, Hideki Maekawa, Susumu Nakayama, Shinobu Ohki, Masataka Tansho, Tadashi Shimizu, Pierre Florian, Dominuqie Massiot

  SOLID STATE IONICS 228 64 - 69 2012年11月 [査読有り][通常論文]
   

  We used magic angle spinning (MAS), multiquantum (MQ)-MAS, and high-temperature (HT) nuclear magnetic resonance (NMR) measurements to investigate the oxide-ion conduction path of oxygen-17 (O-17) in apatite-type lanthanum silicate La-9.33(SiO4)(6)O-2. A highly crystalline apatite-type lanthanum silicate was specifically synthesized for the measurements. MAS and MQ-MAS NMR confirmed that four kinds of oxide-ion sites are present in the structure and showed a small extra peak (<1%) possibly due to an interstitial site. The high-temperature measurements showed that the line shape changed and sharpened with increasing temperature from 200 degrees C, and the peak position shifted at 700 degrees C. The comparison of the results between MAS NMR (room-temperature) and HT static NMR showed the exchange of oxide ions bonded to Si (O1, O2, and O3) but the apparent exchange between the oxide ions (O1, O2, and O3) and the oxide ion at the isolated site (O4) is not observed. The exchange of the oxide ions that are bonded to Si (O1, O2, and O3) suggests that they are the main diffusion species in oxide-ion conductivity. (C) 2012 Elsevier B.V. All rights reserved.
• Transparent conductivity of fluorine-doped anatase TiO2 epitaxial thin films

  Satoru Mohri, Yasushi Hirose, Shoichiro Nakao, Naoomi Yamada, Toshihiro Shimada, Tetsuya Hasegawa

  JOURNAL OF APPLIED PHYSICS 111 9 093528  2012年05月 [査読有り][通常論文]
   

  Transparent conductive anatase TiO2-xFx(F:TiO2) epitaxial thin films were fabricated by reactive pulsed laser deposition with a solid fluorine source. F-doping as high as 1.6 x 10(21) cm(-3) (TiO1.95F0.05) was achieved under optimal growth conditions, and the obtained anatase TiO1.95F0.05 film had a low resistivity of 1.6 x 10(-3) Omega cm and a high internal transmittance of >95%. Furthermore, the refractive index of a TiO1.95F0.05 film was >0.2 less than that of undoped TiO2. By comparing the refractive indices of F:TiO2 and Nb:TiO2, we concluded that the decreased refractive index in F:TiO2 can be attributed to a reduced electronic polarizability due to increased bond ionicity as well as doped electrons. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4712061]
• Fabrication of Piezoelectric Polyurea Films by Alternating Deposition

  Takashi Yanase, Tetsuya Hasegawa, Taro Nagahama, Toshihiro Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS 51 4 041604  2012年04月 [査読有り][通常論文]
   

  We demonstrate that polyurea films can be prepared by alternating deposition with automated deposition control involving quartz crystal microbalance monitoring and optical source heating. The thickness of the films was linearly controlled by changing the repetition time of deposition, and the stoichiometry obtained was much higher than +/- 5%. The surface roughness of a 600-nm-thick film was 0.5 nm, which ensures the nm thickness control of the deposited polymers. The piezoelectricity of the films was confirmed by directly measuring the current transient induced by mechanical stress and by measuring the capacitance change induced by electric field. (C) 2012 The Japan Society of Applied Physics
• Change in the Morphology of the Terrace Edges on Graphite Surfaces by Electrochemical Reduction

  Shosei Kubota, Tetsu Yonezawa, Taro Nagahama, Toshihiro Shimada

  CHEMISTRY LETTERS 41 2 187 - 188 2012年02月 [査読有り][通常論文]
   

  We found that graphite surfaces can be etched by electrochemical reduction in sulfuric acid. Terraces with straight edges crossing with 60 degrees-multiple angles were found on surfaces by AFM observation. It suggests that crystallographic edges can be formed at room temperature in a controlled manner. Layer-by-layer etching of graphene sheets was possible by tuning the etching condition.
• Computational Analysis of Thermal Energetic Disorder in a Pentacene Crystal: Temperature Dependence of Trap Levels and Possible Novel Thermoelectric Contribution

  Toshihiro Shimada, Yu Ikuta, Yuya Tsuchida, Manabu Ohtomo, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 4 6 061601  2011年06月 [査読有り][通常論文]
   

  In organic semiconductors, the sudden appearance of deep traps (30-100 meV) below 100-200 K is frequently observed experimentally even in highly crystalline films and single crystals. We analyzed this phenomenon by molecular dynamics combined with semi-empirical quantum chemical calculation, and found that defect levels are concealed by thermal disorder at high temperatures but appear as hole traps at low temperatures. We propose that the thermal energetic disorder may lead to a considerably large thermoelectric effect in organic semiconductors. (C) 2011 The Japan Society of Applied Physics
• Enhanced Carrier Transport in Uniaxially (001)-Oriented Anatase Ti0.94Nb0.06O2 Films Grown on Nanosheet Seed Layers

  Naoomi Yamada, Tatsuo Shibata, Kenji Taira, Yasushi Hirose, Shoichiro Nakao, Ngoc Lam Huong Hoang, Taro Hitosugi, Toshihiro Shimada, Takayoshi Sasaki, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 4 4 045801  2011年04月 [査読有り][通常論文]
   

  Uniaxially (001)-oriented anatase Ti0.94Nb0.06O2 films were sputtered on a seed layer of glass covered with Ca2Nb3O10 nanosheets (CNO-NS). The films had an effective electron mass of 0.7m(0) (m(0) denotes the free electron mass), which was smaller than that of randomly oriented films, i.e., 0.9m(0). The as-grown films exhibited a low resistivity of 7.6 x 10(-4) Omega cm. Postdeposition annealing under H-2 atmosphere further reduced the resistivity to 4.0 x 10(-4) Omega cm. This value is comparable with that of conventional transparent conducting oxides. Results indicate that sputtering using CNO-NS is promising for the fabrication of highly conductive Ti1-xNbxO2 electrodes on glass. (C) 2011 The Japan Society of Applied Physics
• Enhanced Carrier Transport in Uniaxially (001)-Oriented Anatase Ti0.94Nb0.06O2 Films Grown on Nanosheet Seed Layers

  Naoomi Yamada, Tatsuo Shibata, Kenji Taira, Yasushi Hirose, Shoichiro Nakao, Ngoc Lam Huong Hoang, Taro Hitosugi, Toshihiro Shimada, Takayoshi Sasaki, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 4 4 045801  2011年04月 [査読有り][通常論文]
   

  Uniaxially (001)-oriented anatase Ti0.94Nb0.06O2 films were sputtered on a seed layer of glass covered with Ca2Nb3O10 nanosheets (CNO-NS). The films had an effective electron mass of 0.7m(0) (m(0) denotes the free electron mass), which was smaller than that of randomly oriented films, i.e., 0.9m(0). The as-grown films exhibited a low resistivity of 7.6 x 10(-4) Omega cm. Postdeposition annealing under H-2 atmosphere further reduced the resistivity to 4.0 x 10(-4) Omega cm. This value is comparable with that of conventional transparent conducting oxides. Results indicate that sputtering using CNO-NS is promising for the fabrication of highly conductive Ti1-xNbxO2 electrodes on glass. (C) 2011 The Japan Society of Applied Physics
• Epitaxial Growth of Organic Molecules on Vicinal Surfaces of Single Crystals

  Toshihiro Shimada, Takafumi Sakurada, Atsushi Koma

  MRS Proceedings 451 2011年02月10日
• Strong Pressure Effect in the Sublimation from Tetracene Single Crystals and Development of Surface Cleaning Technique for Organic Semiconductors

  Manabu Ohtomo, Kenji Itaka, Tetsuya Hasegawa, Toshihiro Shimada

  APPLIED PHYSICS EXPRESS 4 2 021601  2011年02月 [査読有り][通常論文]
   

  We studied the sublimation of tetracene single crystals under vacuum and 1 atm inert gas to develop the surface cleaning technique for organic semiconductors. It was found that the microscopic sublimation behavior is strongly dependent on the gas pressure. Nanometer-scale roughening was observed after heating in vacuum, and layer-by-layer sublimation was observed under 1 atm Ar gas. Reflection high energy electron diffraction analysis of the topmost surface showed streak patterns, indicating that surface contaminants were successfully removed. (C) 2011 The Japan Society of Applied Physics
• Strong Pressure Effect in the Sublimation from Tetracene Single Crystals and Development of Surface Cleaning Technique for Organic Semiconductors

  Manabu Ohtomo, Kenji Itaka, Tetsuya Hasegawa, Toshihiro Shimada

  APPLIED PHYSICS EXPRESS 4 2 021601  2011年02月 [査読有り][通常論文]
   

  We studied the sublimation of tetracene single crystals under vacuum and 1 atm inert gas to develop the surface cleaning technique for organic semiconductors. It was found that the microscopic sublimation behavior is strongly dependent on the gas pressure. Nanometer-scale roughening was observed after heating in vacuum, and layer-by-layer sublimation was observed under 1 atm Ar gas. Reflection high energy electron diffraction analysis of the topmost surface showed streak patterns, indicating that surface contaminants were successfully removed. (C) 2011 The Japan Society of Applied Physics
• The Electronic Structures of Fullerene/Transition-Metal Hybrid Material

  Yoshihiro Matsumoto, Seiji Sakai, Hiroshi Naramoto, Norie Hirao, Yuji Baba, Isamu Sugai, Koki Takanashi, Toshihiro Shimada, Yoshihito Maeda

  Materials Research Society Symposium Proceedings 1081 2011年02月 [査読有り][通常論文]
  
• Epitaxial Growth and Charge Density Wave of TaSe₂

  Toshihiro Shimada, Fumio S. Ohuchi, Bruce A. Parkinson

  MRS Proceedings 230 2011年02月
• Rheed Oscillation During the Epitaxial Growth of Layered Materials

  Toshihiro Shimada, Fumio S. Ohuchi, Atsushi Koma

  MRS Proceedings 208 2011年02月
• Fabrication of transparent conductive W-doped SnO2 thin films on glass substrates using anatase TiO2 seed layers

  Shoichiro Nakao, Naoomi Yamada, Taro Hitosugi, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 8, NO 2 8 2 543  2011年 [査読有り][通常論文]
   

  Pulsed laser deposition was used to grow W-doped SnO2 (WTO) thin films on glass substrates. By using 10-nm-thick polycrystalline anatase TiO2 seed layers formed on the glass substrates, the lowest resistivity of 3.5 x 10(-4) Omega cm, with a mobility of 84 cm(2)V(-1)s(-1) and a carrier concentration of 2.1 x 10(20) cm(-3), was obtained at a W concentration of 1.5 at.%. An optimized WTO film with a sheet resistance of 9.1 Omega/square exhibited an optical transmittance of over 70% at wavelengths ranging from 400 to 1950 nm. These transport and optical properties are comparable to those of Ta-doped SnO2. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
• Ultrasensitive and Rapid Measurement of Water Vapor Transmission Rate in Barrier Materials

  Toshihiro Shimada, Yoichiro Nakano, Yoshikazu Takahashi, Toshiyuki Kanno

  IDW'11: PROCEEDINGS OF THE 18TH INTERNATIONAL DISPLAY WORKSHOPS, VOLS 1-3 1717 - 1720 2011年 [査読有り][通常論文]
   

  We have developed an instrument for ultrasensitive (<10(-6) g/m(2)/day) and rapid (<1 day) measurement of water vapor transmission rate in gas barrier materials. Water vapor that has permeated through the barrier in atmospheric carrier gas is condensed by a cold trap and transferred to mass spectrometer in ultrahigh vacuum.
• High magnetic field effect in organic light emitting diodes

  Yuichiro Goto, Takuya Noguchi, Utahito Takeuchi, Kunitada Hatabayashi, Yasushi Hirose, Takayuki Uchida, Takehiko Sasaki, Tetsuya Hasegawa, Toshihiro Shimada

  ORGANIC ELECTRONICS 11 7 1212 - 1216 2010年07月 [査読有り][通常論文]
   

  Fluorescent and phosphorescent organic light emitting diodes (OLEDs) were measured in high magnetic field up to 9 T. The current efficiency steeply increased below 100 mT as reported but gradually decreased when the field was larger. In the range of 0.1-6.5 T, the decrease was proportional to the square of the magnetic field, whereas in the range between 6.5 and 9 T, it was proportional to the square root of the magnetic field. In contrast, phosphorescent OLED did not show magnetic field dependence. Unipolar devices of n-type Alq(3) (tris-(8-hydroxyquinolino) aluminum) and p-type alpha-NPD (N',N'-di(naphthalene-1-yl)-N,N'-dipheyl-benzidine) showed positive linear magnetoresistance only for minority carriers. The mechanism of the quadratic dependence of the electroluminescent intensity is discussed based on the experimental results. (c) 2010 Elsevier B.V. All rights reserved.
• High magnetic field effect in organic light emitting diodes

  Yuichiro Goto, Takuya Noguchi, Utahito Takeuchi, Kunitada Hatabayashi, Yasushi Hirose, Takayuki Uchida, Takehiko Sasaki, Tetsuya Hasegawa, Toshihiro Shimada

  ORGANIC ELECTRONICS 11 7 1212 - 1216 2010年07月 [査読有り][通常論文]
   

  Fluorescent and phosphorescent organic light emitting diodes (OLEDs) were measured in high magnetic field up to 9 T. The current efficiency steeply increased below 100 mT as reported but gradually decreased when the field was larger. In the range of 0.1-6.5 T, the decrease was proportional to the square of the magnetic field, whereas in the range between 6.5 and 9 T, it was proportional to the square root of the magnetic field. In contrast, phosphorescent OLED did not show magnetic field dependence. Unipolar devices of n-type Alq(3) (tris-(8-hydroxyquinolino) aluminum) and p-type alpha-NPD (N',N'-di(naphthalene-1-yl)-N,N'-dipheyl-benzidine) showed positive linear magnetoresistance only for minority carriers. The mechanism of the quadratic dependence of the electroluminescent intensity is discussed based on the experimental results. (c) 2010 Elsevier B.V. All rights reserved.
• Fabrication of highly conductive Ta-doped SnO2 polycrystalline films on glass using seed-layer technique by pulse laser deposition

  Shoichiro Nakao, Naoomi Yamada, Taro Hitosugi, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  THIN SOLID FILMS 518 11 3093 - 3096 2010年03月 [査読有り][通常論文]
   

  We discuss the fabrication of highly conductive Ta-doped SnO2 (Sn1-xTaxO2: ITO) thin films on glass by pulse laser deposition. On the basis of the comparison of X-ray diffraction patterns and resistivity (rho) values between epitaxial films and polycrystalline films deposited on bare glass, we proposed the use of seed-layers for improving the conductivity of the TTO polycrystalline films. We investigated the use of rutile TiO2 and NbO2 as seed-layers; these are isostructural materials of SnO2, which are expected to promote epitaxial-like growth of the TTO films. The films prepared on the 10-nm-thick seed-layers exhibited preferential growth of the TTO (110) plane. The TTO film with x=0.05 on rutile TiO2 exhibited p = 3.5 x 10(-4)Omega cm, which is similar to those of the epitaxial films grown on Al2O3 (0001). (C) 2009 Elsevier B.V. All rights reserved.
• Transparent conducting Nb-doped anatase TiO2 (TNO) thin films sputtered from various oxide targets

  Naoomi Yamada, Taro Hitosugi, Junpei Kasai, Ngoc Lam Huong Hoang, Shoichiro Nakao, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  THIN SOLID FILMS 518 11 3101 - 3104 2010年03月 [査読有り][通常論文]
   

  Transparent conducting Nb-doped anatase TiO2 (TNO) epitaxial films were sputtered from TiO2-, Ti2O3-, and Ti-based targets at various oxygen partial pressures (Po-2). Using the TiO2- and Ti2O3-based targets, highly conductive films showing a resistivity (rho) of similar to 3 x 10(-4) Omega cm could be formed without postdeposition treatment. In the case of the TNO films formed from the Ti-based target, reductive annealing had to be carried out at a temperature of 600 degrees C to achieve similar resistivity values. Thus, the use of oxide targets is preferable to obtain as-grown transparent conducting TNO films. In particular, the Ti2O3-based target is practically advantageous, because it offers a wide range of optimal Po-2 values at which p values of the order of 10(-4) Omega cm are achievable. (C) 2009 Elsevier B.V. All rights reserved.
• Very high temperature annealing effect on amorphous carbon films grown on refractory oxide substrates by pulsed laser deposition

  Takuya Noguchi, Toshihiro Shimada, Takashi Chiba, Masao Terada, Tetsuya Hasegawa

  DIAMOND AND RELATED MATERIALS 19 2-3 107 - 109 2010年02月 [査読有り][通常論文]
   

  We have carried out very high temperature heat treatment at 1400-2700 degrees C of about 10 nm-thick amorphous carbon thin films deposited on refractory substrates MgO, Al2O3, and yttria-stabilized zirconia (YSZ) using pulsed laser deposition techniques. After the annealing, a few nanometer scale sp(2) crystallization of the films and a large corrugation with a height of more than 1 mu m were observed by Raman spectroscopy analysis and optical/atomic force microscopes, respectively. The corrugation is probably caused by tire formation of gases at the film/substrate interface during the heat treatment. (C) 2009 Elsevier B.V. All rights reserved.
• Transport properties and electronic states of anatase Ti1-xWxO2 epitaxial thin films

  Utahito Takeuchi, Akira Chikamatsu, Taro Hitosugi, Hiroshi Kumigashira, Masaharu Oshima, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  JOURNAL OF APPLIED PHYSICS 107 2 023705  2010年01月 [査読有り][通常論文]
   

  We have investigated the transport properties and electronic states of W-doped anatase TiO2 (Ti1-xWxO2) fabricated by pulsed-laser deposition. Based on transport and photoemission spectroscopy (PES) measurements, we discuss the conduction mechanism of Ti1-xWxO2, focusing on the valence state of W. The Ti0.95W0.05O2 film deposited under optimized conditions showed a resistivity of 2x10(-3) cm at room temperature, which is approximately ten times higher than that of Ti0.94Nb0.06O2. This is mainly due to the lower carrier density in Ti1-xWxO2 films. From PES measurements of Ti0.91W0.09O2 films, we observed the finite density of states originating from O 2p hybridized with W near the top of the valence band. However, we could not find any states at the same position in the Ti0.94Nb0.06O2 films. In addition, the density of states near the Fermi level [N(E-F)] was found to be quite low in the Ti0.91W0.09O2 films. Indeed, this is in sharp contrast to Ti0.94Nb0.06O2, which indicates a remarkably high N(E-F) value assigned to the bottom of the Ti 3d conduction band. The difference in transport properties between Ti1-xWxO2 and Ti1-xNbxO2 can be attributed to the existence of impurity states that trap carriers associated with doped W atoms.
• Highly Sensitive and Rapid Measurement of Gas Barrier Properties of Flexible Films and Sealing Resins Based on a Low Temperature Trap and Mass Spectroscopy

  Toshihiro Shimada, Yoshikazu Takahashi, Toshiyuki Kanno

  APPLIED PHYSICS EXPRESS 3 2 021701  2010年 [査読有り][通常論文]
   

  We developed a novel apparatus for the measurement of the gas barrier properties of soft materials. The measurement principle is based on the use of a low temperature trap to transfer the permeated vapor from the sample space under atmospheric pressure to the mass spectrometer situated in an ultrahigh vacuum. We have demonstrated that the sensitivity, dynamic range and lead time for the measurement can be significantly improved from those previously reported. It was revealed that the diffusion time in a polymer film must be considered in the measurement of high barrier films. (C) 2010 The Japan Society of Applied Physics DOI: 10.1143/APEX.3.021701
• High Mobility Exceeding 80 cm(2) V-1 s(-1) in Polycrystalline Ta-Doped SnO2 Thin Films on Glass Using Anatase TiO2 Seed Layers

  Shoichiro Nakao, Naoomi Yamada, Taro Hitosugi, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 3 3 031102  2010年 [査読有り][通常論文]
   

  High-mobility Ta-doped SnO2 (TTO) thin films were grown on glass substrates by pulsed laser deposition using a seed-layer technique. The use of 10-nm-thick polycrystalline anatase TiO2 seed layers was found to lead to the preferred growth of (200)-oriented TTO films, resulting in a 30% increase in the carrier density and a more than two times increase in mobility, compared to films grown directly on the glass substrates. The highest mobility obtained was 83 cm(2) V-1 s(-1) with a resistivity of 2.8 x 10(-4) Omega cm, whereas the film with the lowest resistivity of 1.8 x 10(-4) Omega cm had a mobility of 60 cm(2) V-1 s(-1). (C) 2010 The Japan Society of Applied Physics
• Magnetic and Transport Properties of Anatase TiO2 Codoped with Fe and Nb

  Enju Sakai, Akira Chikamatsu, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 3 4 043001  2010年 [査読有り][通常論文]
   

  We have measured the magnetic and transport properties of FexNbyTi1-x-yO2-delta (x = 0.06, y = 0, 0.1, 0.03) films deposited by pulsed laser deposition at various partial oxygen pressures (PO2). The Fe and Nb codoped films have a carrier concentration of > 3 x 10(20) cm(-3), which is independent of PO2 and far exceeds the critical carrier concentration for ferromagnetic ordering in Fe0.06Ti0.94O2-delta (1 x 10(19) cm(-3)). Room-temperature ferromagnetism was observed only when deposition was conducted in reducing atmospheres (i.e., PO2 <= 1 x 10(-6) Torr) for all the FexNbyTi1-x-yO2-delta films, indicating that there is a critical oxygen vacancy density for the ferromagnetic transition. (C) 2010 The Japan Society of Applied Physics
• Carrier Compensation by Excess Oxygen Atoms in Anatase Ti0.94Nb0.06O2+δ Epitaxial Thin Films

  Hiroyuki Nogawa, Taro Hitosugi, Akira Chikamatsu, Shoichiro Nakao, Yasushi Hirose, Toshihiro Shimada, Hiroshi Kumigashira, Masaharu Oshima, Tetsuya Hasegawa

  Jpn. J. Appl. Phys. 49 4 041102  2010年 [査読有り][通常論文]
   

  We report the effect of post-deposition annealing on the electrical transport properties of anatase Ti0.94Nb0.06O2 (TNO) epitaxial thin films. Annealing TNO films in pure oxygen drastically suppressed the carrier density (n(e)). A high n(e) of the order of 10(21) cm(-3) was recovered by successive annealing in pure hydrogen. Core-level X-ray photoemission spectroscopy revealed that Ti and Nb respectively exist as tetravalent and pentavalent ions in fully oxidized samples. The concentration of Nb5+ relative to that of Nb4+ tends to increase with O-2 annealing, suggesting that carriers released by Nb donors are compensated by electron-killing impurity states created by O-2 annealing. Based on these findings, we propose that excess oxygen atoms incorporated by O-2 annealing occupy interstitial sites and behave as deep acceptor states, which compensate electron carriers generated by Nb doping. Resonant valence-band photoemission spectroscopy directly confirmed the formation of deep acceptor states associated with oxygen annealing. (C) 2010 The Japan Society of Applied Physics
• Electric Double Layer Gate Field-Effect Transistors Based on Si

  Takashi Yanase, Toshihiro Shimada, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS 49 4 04DK06  2010年 [査読有り][通常論文]
   

  Electric double layer field-effect transistors (EDL-FETs) were fabricated using single crystal Si wafer as the active semiconductor and various characteristics were studied including dynamic response against step-function gate bias. The static FET mobility was more than 100 cm(2) V-1 s(-1). The response time of the drain current was 20 mu s for ionic liquid and 3 ms for poly(ethylene glycol) (PEG) solution of LiBF4. Unexpected fast response was observed at a certain "speed up bias'' condition. This effect will be useful to switching circuits using EDL-FETs. (C) 2010 The Japan Society of Applied Physics
• Very high temperature chemical vapor deposition of new carbon thin films using organic semiconductor molecular beam sources

  Takuya Noguchi, Toshihiro Shimada, Akinori Hanzawa, Tetsuya Hasegawa

  THIN SOLID FILMS 518 2 778 - 780 2009年11月 [査読有り][通常論文]
   

  We carried out the preparation and characterization of new carbon films deposited using an organic molecular beam deposition apparatus with very high substrate temperature (from room temperature to 2670 K), which we newly developed. When we irradiated molecular beam of organic semiconductor perylene tetracarboxylic acid dianhydride (PTCDA) on Y(0.07)Zr(0.93)O(2) (111) at 2170 K, a new carbon material was formed via decomposition and fusing of the molecules. The films were characterized with an atomic force microscope (AFM), Raman spectroscopy, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Zirconium carbide (ZrC) films were identified beneath the topmost carbon layer by XRD and XPS analyses, which results from chemical reactions of the substrate and the molecules. Partially graphitized aromatic rings of PTCDA were observed from Raman spectroscopy. The present technique - very high temperature chemical vapor deposition using organic semiconductor sources - will be useful to study a vast unexplored field of covalent carbon solids. (C) 2009 Elsevier B.V. All rights reserved.
• In-Situ TEM Observations of the Crystallization Process of Solution-Prepared MoS2 Amorphous Particles

  Akinori Hanzawa, Toshihiro Shimada, Tetsuya Hasegawa, Takahiro Sato, Takeo Kamino, Tetsu Yonezawa

  JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 9 11 6736 - 6740 2009年11月 [査読有り][通常論文]
   

  The crystallization of polymer-mixed amorphous molybdenum sulfide was observed in-situ by a TEM equipped with a heated specimen holder. High electron beam irradiation induced the formation of a crystal structure with a lattice spacing of 0.62 nm, which corresponds to the layer spacing of MoS2. With a lower electron dose, a possible new crystal structure of molybdenum sulfide with several fringe spacings was identified at room temperature. An ordered layered structure Of MoS2 appeared after annealing at 600 degrees C. The completely different crystal phase found here might be responsible for the high temperature required for the formation of the MoS2 layered structure.
• Direct Observation of Gas Phase Nucleation during Physical Vapor Transport Growth of Organic Single Crystals Using a Transparent Furnace

  Miyamoto S, Shimada T, Ohtomo M, Chikamatsu A, Hasegawa T

  Japanese Journal of Applied Physics 48 11 118003-1 - 118003-2 The Japan Society of Applied Physics 2009年11月 [査読有り][通常論文]
   

  We observed the physical vapor transport growth of tetracene (C18H12) using a transparent furnace. We found that free-standing small crystals are formed in the gas flow and sometimes stick on the solid surface and become the seeds for larger crystals. A theoretically predicted convection was observed by tracking the trajectory of flowing crystal particles.
• Fabrication of EuTiO3 Epitaxial Thin Films by Pulsed Laser Deposition

  Kunitada Hatabayashi, Taro Hitosugi, Yasushi Hirose, Xianqiang Cheng, Toshihiro Shimada, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS 48 10 2009年10月 [査読有り][通常論文]
   

  We have fabricated high-quality epitaxial EuTiO3(100) films on SrTiO3 substrates by pulsed laser deposition. In situ reflection high-energy electron diffraction (RHEED) monitoring revealed clear intensity oscillation, indicating layer-by-layer growth of EuTiO3. Furthermore, the obtained films had atomically flat surfaces with a step-terrace structure. From magnetization vs temperature measurements, we confirmed that the EuTiO3 films have antiferromagnetic ordering with a Neel temperature of 3.7 K, and that they could be transformed to a ferromagnetic state by applying a magnetic field. We also found that the magnetic properties of the EuTiO3 films are sensitive to cell volume, as predicted by recent first-principles band calculations. (C) 2009 The Japan Society of Applied Physics
• Band dispersion of quasi-single crystal thin film phase pentacene monolayer studied by angle-resolved photoelectron spectroscopy

  Manabu Ohtomo, Tadamasa Suzuki, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS LETTERS 95 12 123308  2009年09月 [査読有り][通常論文]
   

  Intermolecular band dispersion of thin film phase pentacene grown epitaxially on step-bunched root 3 x root 3 Bi-Si(111) was investigated using angle resolved photoemission spectroscopy at 130 K. We evaluated the transfer integrals using two-dimensional tight-binding fit to the experimental dispersion and found that adjacent molecules in Gamma-M direction have the strongest coupling as predicted. The estimated effective mass at the top of the valence band was isotropic and ranged between 0.8 and 1.0 of the electron mass. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3232205]
• Direct growth of transparent conducting Nb-doped anatase TiO2 polycrystalline films on glass

  Naoomi Yamada, Taro Hitosugi, Junpei Kasai, Ngoc Lam Huong Hoang, Shoichiro Nakao, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  JOURNAL OF APPLIED PHYSICS 105 12 123702  2009年06月 [査読有り][通常論文]
   

  This paper proposes a novel sputter-based method for the direct growth of transparent conducting Ti1-xNbxO2 (TNO) polycrystalline films on glass, without the need for any postdeposition treatments, by the use of an initial seed-layer. Anatase TNO epitaxial films grown on LaAlO3 (100) substrates under a reducing atmosphere exhibited a low resistivity (rho) of (3-6) x 10(-4) Omega cm. On glass, however, highly resistive rutile phase polycrystalline films (rho similar to 100 Omega cm) formed preferentially under the same conditions. These results suggest that epitaxial stabilization of the oxygen-deficient anatase phase occurs on lattice-matched substrates. To produce a similar effect on a glass surface, we deposited a seed-layer of anatase TNO with excellent crystallinity under an increased oxygen atmosphere. As a result, anatase phase TNO polycrystalline films could be grown even under heavily reducing atmospheres. An optimized film exhibited rho = 1.1 x 10(-3) Omega cm and optical absorption lower than 10% in the visible region. This rho value is more than one order of magnitude lower than values reported for directly deposited TNO polycrystalline films. This indicates that the seed-layer method has considerable potential for producing transparent conducting TNO polycrystalline films on glass. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3148267]
• Large electron mass anisotropy in a d-electron-based transparent conducting oxide: Nb-doped anatase TiO2 epitaxial films

  Yasushi Hirose, Naoomi Yamada, Shoichiro Nakao, Taro Hitosugi, Toshihiro Shimada, Tetsuya Hasegawa

  PHYSICAL REVIEW B 79 16 165108  2009年04月 [査読有り][通常論文]
   

  Electron mass anisotropy in the Nb-doped anatase TiO2 (TNO) was determined by polarized infrared spectroscopy measurements for (012)-oriented TNO epitaxial films. The electron mass along the c axis, m(< 001 >)(*), derived by Drude analyses, was found to be 0.5-3.3 m(0), which was 3-6 times larger than that along the a axis, m(< 100 >)(*), 0.2-0.6 m(0). This large anisotropy was attributed to not only the anisotropic crystal structure but also the d-orbital-dominated conduction band. These results indicate that control of crystallographic orientation is of crucial importance for realizing high conductivity in polycrystalline TNO films.
• Random Telegraphic Conductance Fluctuation at Au-Pentacene-Au Nanojunctions

  Yuk Kihira, Toshihiro Shimada, Yutaka Matsuo, Eiichi Nakamura, Tetsuya Hasegawa

  NANO LETTERS 9 4 1442 - 1446 2009年04月 [査読有り][通常論文]
   

  Random telegraphic noises with a preferential jump height around 0.018G(0) were observed in the conductance traces of the Au-pentacene-Au junctions. The distribution of the plateau lifetime obeyed an exponential distribution, but the decay constants were independent of the height of the adjacent conductance jumps or the measurement temperature. This result, along with the buckyferrocene (Fe(C-60(CH3)(5))C5H5) result, suggests that the conductance fluctuation originates from the current-induced geometrical fluctuation around a single molecule.
• Random Telegraphic Conductance Fluctuation at Au-Pentacene-Au Nanojunctions

  Yuk Kihira, Toshihiro Shimada, Yutaka Matsuo, Eiichi Nakamura, Tetsuya Hasegawa

  NANO LETTERS 9 4 1442 - 1446 2009年04月 [査読有り][通常論文]
   

  Random telegraphic noises with a preferential jump height around 0.018G(0) were observed in the conductance traces of the Au-pentacene-Au junctions. The distribution of the plateau lifetime obeyed an exponential distribution, but the decay constants were independent of the height of the adjacent conductance jumps or the measurement temperature. This result, along with the buckyferrocene (Fe(C-60(CH3)(5))C5H5) result, suggests that the conductance fluctuation originates from the current-induced geometrical fluctuation around a single molecule.
• X-ray absorption spectroscopy and magnetic circular dichroism in codeposited C-60-Co films with giant tunnel magnetoresistance

  Matsumoto Yoshihiro, Sakai Seiji, Takagi Yasumasa, Nakagawa Takeshi, Yokoyama Toshihiko, Shimada Toshihiro, Mitani Seiji, Naramoto Hiroshi, Maeda Yoshihito

  CHEMICAL PHYSICS LETTERS 470 4-6 244 - 248 2009年03月05日 [査読有り][通常論文]
  
• Fabrication of TiO2-based transparent conducting oxide on glass and polyimide substrates

  T. Hitosugi, N. Yamada, N. L. H. Hoang, J. Kasai, S. Nakao, T. Shimada, T. Hasegawa

  THIN SOLID FILMS 517 10 3106 - 3109 2009年03月 [査読有り][通常論文]
   

  We report on preparation and properties of anatase Nb-doped TiO2 transparent conducting oxide films on glass and polyimide substrates. Amorphous Ti0.96Nb0.04O2 films were deposited at room temperature by using sputtering, and were then crystallized through annealing under reducing atmosphere. Use of a seed layer substantially improved the crystallinity and resistivity (rho) of the films. We attained rho=9.2 X 10(-4) Omega cm and transmittance of similar to 70% in the visible region on glass by annealing at 300 degrees C in vacuum. The minimum rho of 7.0 x 10(-4) Omega cm was obtained by 400 degrees C annealing in pure H-2. (C) 2008 Elsevier B.V. All rights reserved.
• Detailed Investigation on the Possibility of Nanoparticles of Various Metal Elements for Surface-Assisted Laser Desorption/Ionization Mass Spectrometry

  Tetsu Yonezawa, Hideya Kawasaki, Akira Tarui, Takehiro Watanabe, Ryuichi Arakawa, Toshihiro Shimada, Fumitaka Mafune

  ANALYTICAL SCIENCES 25 3 339 - 346 2009年03月 [査読有り][通常論文]
   

  In this paper, we describe systematic detailed considerations of the feasibility of using various metal nanoparticles for organic-matrix-free surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). In order to avoid the influence of organic molecules on the nanoparticles, stabilizer-free bare nanoparticles of Ag, Au, Cu and Pt were prepared by laser ablation. Although all metal nanoparticles absorbed N-2 laser light (337 nm) energy, the performance of desorption/ionization of a representative peptide, angiotensin 1, strongly depended on the metal element. Citrate buffer was used as a proton source; it reduced the amount of alkali cation adducts present. Then, protonated molecules of analytes predominated in the mass spectra when Au and Pt nanoparticles were used. Pt nanoparticles showed the highest performance in SALDI-MS, owing to their smaller heat conductivity and higher melting temperature. The selective desorption of a cationic surfactant with longer alkyl chains and a peptide with methionine was also observed.
• ペンタセン超薄膜のエピタキシャル成長と光電子分光

  島田 敏宏, 鈴木 維允, 大伴 真名歩, 長谷川 哲也

  表面科学 : hyomen kagaku = Journal of the Surface Science Society of Japan 30 1 7 - 10 The Surface Science Society of Japan 2009年01月10日 

  We developed a technique to prepare highly ordered thin films of organic molecular semiconductors. A quasi single crystalline monolayer of thin film phase pentacene was epitaxially grown on a substrate with a nm scale template prepared by step bunching of Si(111) surface. Band dispersion of the films was measured by angle resolved photoelectron spectroscopy at different temperatures and transfer integrals were derived from tight binding fit to the dispersion observed at 130 K. When the temperature was elevated to 300 K the second derivative plot of the photoelectron spectra became broader and the band dispersion was lost in two directions, whereas the dispersion was still observed in one direction. This finding suggests the anisotropy in phonon scattering, which determines the carrier mobility in the organic semiconductors at room temperature.
• Electron spectroscopy and near infrared photocurrent measurement of working organic thin film fets

  Toshihiro Shimada, Manabu Ohtomo, Tetsuya Hasegawa

  Integrated Circuits, Photodiodes and Organic Field Effect Transistors 161 - 183 2009年01月01日 

  This contribution is intended to provide a combined view of spectroscopic studies on electronic states in working organic thin film FETs based on our experiments. Three kinds of spectroscopic techniques are presented: Ultraviolet Photoelectron Spectroscopy (UPS), Electron Energy Loss Spectroscopy(EELS), and near infrared photocurrent spectroscopy (NIRPCS). Information on energy levels, effective mass, location of field induced carriers and gap states related with traps and off-current of the devices can be obtained from those spectroscopic techniques.
• Hatabayashi, K Hitosugi, T Hirose, Y Cheng, XQ Shimada, T Hasegawa, T

  Fabrication of EuTi, Epitaxial Thin Films by Pulsed Laser Deposition

  Japanese Journal of Applied Physics 48 100208  2009年 [査読有り][通常論文]
  
• Multiple-scattering approach to Ti L-2,L-3-edge XMCD analyses for Co doped TiO2

  Takashi Maruyama, Takumi Ohtsuki, Enju Sakai, Hitoshi Abe, Toshihiro Shimada, Tetsuya Hasegawa, Shin-ichi Nagamatsu, Takashi Fujikawa

  14TH INTERNATIONAL CONFERENCE ON X-RAY ABSORPTION FINE STRUCTURE (XAFS14), PROCEEDINGS 190 2009年 [査読無し][通常論文]
   

  We have measured Ti L-2,L-3-edge X-ray magnetic circular dichroism (XMCD) spectra of Co doped anatase TiO2 (Co0.05Ti0.95O2), where nonzero XMCD spectra have been observed even at Ti L-2,L-3-edge. In order to understand the reason why the XMCD signals are observed at Ti L-2,L-3-edge, we have applied the relativistic multiple-scattering approach to the analyses of the observed XMCD spectra. The results show that the Ti L-2,L-3-edge XMCD spectra are dominated by the spin-dependent exchange scatterings on the spin-polarized Co sites. We find a good agreement with the observed L-3 XMCD spectra. The calculated XMCD spectra are rather sensitive to the spin moment on the X-ray absorbing Ti. We conclude that the spin moment on Ti site is very small and antiparallel to that on Co. The calculated results also show that the observed Ti L-2,L-3-edge XMCD signals arise from the Ti atoms within about 4 A from spin-polarized Co atoms.
• Artificial Grain Alignment of Organic Crystalline Thin Films

  Toshihiro Shimada

  ARTIFICIALLY INDUCED GRAIN ALIGNMENT IN THIN FILMS 1150 139 - 150 2009年 [査読有り][通常論文]
   

  It is important to obtain single crystalline organic thin films for electronics and optics applications. Due to the mismatching in the crystal symmetry, it is difficult to align the crystalline grains of organic molecular films even on single crystalline surfaces. We have developed several techniques for the artificial grain alignment in organic epitaxial growth. (1) Use of nanoscale-textured surfaces prepared by step bunching of vicinally-cut single crystalline surfaces, in which the height of the steps is critically important. (2) Application of external electric field. (3) Optical excitation of the molecules which can be applied to the polar semiconducting molecules. These techniques might be applicable to other materials including ionic materials and ferroelectrics.
• Low-temperature fabrication of transparent conducting polycrystalline Nb-doped TiO2 films by sputtering

  Hoang N.L.H, Yamada N, Hitosugi T, Kasai J, Nakao S, Shimada T, Hasegawa T

  Materials Research Society Symposium Proceedings 1109 25 - 30 2009年 [査読有り][通常論文]
  
• Large electron mass anisotropy in anatase Ti1-xNb xO2 transparent conductor

  Hirose Y, Yamada N, Nakao S, Hitosugi T, Shimada T, Konuma S, Hasegawa T

  Materials Research Society Symposium Proceedings 1109 86 - 91 2009年 [査読有り][通常論文]
  
• Growth of transparent conducting Nb-doped anatase TiO2 thin films on glass using seed layers

  Yamada N, Hitosugi T, Nakao S, Kasai J, Hirose Y, Hoang N.L.H, Shimada T, Hasegawa T

  Materials Research Society Symposium Proceedings 1109 15 - 24 2009年 [査読有り][通常論文]
  
• Step-bunched Bi-terminated Si(111) surfaces as a nanoscale orientation template for quasisingle crystalline epitaxial growth of thin film phase pentacene

  Toshihiro Shimada, Manabu Ohtomo, Tadamasa Suzuki, Tetsuya Hasegawa, Keiji Ueno, Susumu Ikeda, Koichiro Saiki, Miho Sasaki, Katsuhiko Inaba

  APPLIED PHYSICS LETTERS 93 22 223303  2008年12月 [査読有り][通常論文]
   

  We developed a nanoscale orientation template for quasisingle crystalline epitaxial growth of thin film phase pentacene. By using alpha-3x3 Bi termination of surface dangling bonds on step-bunched vicinal surface of Si(111), thin film phase epitaxial pentacene was grown with the crystal axes aligned to the surface steps. Alignment occurred when the step height was higher than the molecular height. The mechanism of the alignment was examined by calculating the energy of the crystal edge.
• Nucleation on the substrate surfaces during liquid flux-mediated vacuum deposition of rubrene

  Toshihiro Shimada, Yui Ishii, Keiji Ueno, Tetsuya Hasegawa

  JOURNAL OF CRYSTAL GROWTH 311 1 163 - 166 2008年12月 [査読有り][通常論文]
   

  We studied the effect of the substrate materials on the solution-mediated vacuum deposition of organic semiconductor rubrene using liquid flux with a low vapor pressure. We found that bis-2-ethylhexyl phthalate was suitable as the liquid flux. It was revealed that the microscopic crystal shape completely changed when different substrates were used. This result clearly indicates the nucleation of the crystals occurs on the substrate surface submerged in the solution. Epitaxially oriented needle crystals as long as 5 mm were obtained by using Au(111) substrate. (C) 2008 Elsevier B.V. All rights reserved.
• Low-temperature Fabrication of Transparent Conducting Anatase Nb-doped TiO2 Films by Sputtering

  Ngoc Lam Huong Hoang, Naoomi Yamada, Taro Hitosugi, Junpei Kasai, Shoichiro Nakao, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 1 11 115001  2008年11月 [査読有り][通常論文]
   

  We present a low-temperature (similar to 300 degrees C) process for preparing transparent conducting anatase Nb-doped TiO2 (TNO) polycrystalline films by sputtering. We first deposited amorphous films composed of an oxygen-rich bottom layer and oxygen-deficient top layer at room temperature. These films were then crystallized in a reducing atmosphere. The oxygen-rich bottom layer behaved as a seed layer during crystallization of the top layer, resulting in significant improvement of crystallinity and reduction of crystallization temperature. We obtained TNO polycrystalline films showing a resistivity of 6.4 x 10(-4) Omega cm and absorption below 10% in the visible region by post-deposition annealing at 400 degrees C. The developed low-temperature process was applied to fabricating TNO films on plastics and glass with low glass-transition temperature. (C) 2008 The Japan Society of Applied Physics
• Electronic Band Structure of Transparent Conductor: Nb-Doped Anatase TiO2

  Taro Hitosugi, Hideyuki Kamisaka, Koichi Yamashita, Hiroyuki Nogawa, Yutaka Furubayashi, Shoichiro Nakao, Naoomi Yamada, Akira Chikamatsu, Hiroshi Kumigashira, Masaharu Oshima, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS EXPRESS 1 11 111203  2008年11月 [査読有り][通常論文]
   

  We have investigated electronic band structure of a transparent conducting oxide, Nb-doped anatase TiO2 (TNO), by means of first-principles band calculations and photoemission measurements. The band calculations revealed that Nb 4d orbitals are strongly hybridized with Ti 3d ones to form a d-nature conduction band, without impurity states in the in-gap region, resulting in high carrier density exceeding 10(21) cm(-3) and excellent optical transparency in the visible region. Furthermore, we confirmed that the results of valence band and core-level photoemission measurements are consistent with prediction by the present band calculations. (C) 2008 The Japan Society of Applied Physics
• 有機半導体分子の配向薄膜作製と応用

  島田 敏宏

  應用物理 77 11 1332 - 1336 応用物理学会 2008年11月 [査読無し][招待有り]
  
• Structural, electrical and optical propel-ties of sputter-deposited Nb-doped TiO2 (TNO) polycrystalline films

  Naoomi Yamada, Taro Hitosugi, Ngoc Lam Huong Hoang, Yutaka Furubayashi, Yasushi Hirose, Seiji Konuma, Toshihiro Shimada, Tetsuya Hasegawa

  THIN SOLID FILMS 516 17 5754 - 5757 2008年07月 [査読有り][通常論文]
   

  Transparent conductive oxide (TCO) films of polycrystalline Nb-doped TiO2 (TNO) were fabricated by post-annealing reactively sputtered amorphous films under H-2 atmosphere. Carrier transport properties of the H-2-annealed films were found to be strongly dependent on substrate temperature T-s and oxygen content in sputtering atmosphere. A minimum resistivity (rho) of 9.5 x 10(-4) Omega cm and an average visible transmittance of similar to 75% were obtained at T-s = RT and oxygen content of 10%. This rho value is of the same order as those of epitaxial TNO films, indicating that polycrystalline TNO has sufficient potential as a practical TCO suitable for large-area applications. (C) 2007 Elsevier B.V. All rights reserved.
• Transparent conducting properties of anatase Ti0.94Nb0.06O2 polycrystalline films on glass substrate

  T. Haosugi, A. Ueda, S. Nakao, N. Yamada, Y. Furubayashi, Y. Hirose, S. Konuma, T. Shimada, T. Hasegawa

  THIN SOLID FILMS 516 17 5750 - 5753 2008年07月 [査読有り][通常論文]
   

  We report on transparent conducting properties of anatase Ti0.94Nb0.06O2 (TNO) polycrystalline films on glass substrate, and discuss the role of grain crystallinity and grain boundary on resistivity. Thin films of TNO were deposited using pulsed laser deposition at substrate temperature ranging from room temperature to 350 degrees C, with subsequent H-2-annealing at 500 degrees C. Polycrystalline TNO films showed resistivity of 4.5 x 10(-4) Omega cm and 1.5 x 10(-3) Omega cm for films prepared at substrate temperature of room temperature and 250 degrees C, respectively. X-ray diffraction measurements and transmission electron microscopy reveal that grain crystallinity and grain boundary play key roles in conductive films. (C) 2007 Elsevier B.V. All rights reserved.
• Structural study of TiO2-based transparent conducting films

  T. Hitosugi, N. Yamada, S. Nakao, K. Hatabayashi, T. Shimada, T. Hasegawa

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A 26 4 1027 - 1029 2008年07月 [査読有り][通常論文]
   

  We have investigated microscopic structures of sputter and pulsed laser deposited (PLD) anatase Nb-doped TiO2 transparent conducting films, and discuss what causes the degradation of resistivity in sputter-deposited films. Cross-sectional transmission electron microscope and polarized optical microscope images show inhomogeneous intragrain structures and small grains of similar to 10 mu m in sputter-deposited films. From comparison with PLD films, these results suggest that homogeneous film growth is the important factor to obtain highly conducting sputter-deposited film. (C) 2008 American Vacuum Society.
• Graphoepitaxy of sexithiophene and orientation control by surface treatment

  Susumu Ikeda, Koichiro Saiki, Yasuo Wada, Katsuhiko Inaba, Yoshiyasu Ito, Hirokazu Kikuchi, Kazuo Terashima, Toshihiro Shimada

  JOURNAL OF APPLIED PHYSICS 103 8 084313  2008年04月 [査読有り][通常論文]
   

  The factors influencing the graphoepitaxy of organic semiconductor alpha-sexithiophene (6T) on thermally oxidized silicon substrates were studied and it was discovered that a wider pitch in the microgrooves decreased the degree of graphoepitaxy. A more significant finding was that in-plane orientation could be changed by simple surface treatment. On UV/ozone-treated substrates (hydrophilic condition), the b-axis of 6T was parallel to the grooves. Further surface treatment with hexamethyl-disiloxane (under hydrophobic conditions) changed this in-plane orientation by 90 degrees. This change is due to the interaction between the topmost chemical species (functional groups) of the groove walls and organic molecules, a behavior peculiar to organic graphoepitaxy and exploitable for optimal orientation control in device processing. The nucleation and growth processes that cause the graphoepitaxy are discussed, based on the experimental results. (C) 2008 American Institute of Physics.
• Epitaxial strain effects in ultrathin films of squaric acid studied by temperature-dependent electron reflectivity

  Toshihiro Shimada, Iwao Sugiura, Koichiro Saiki

  JAPANESE JOURNAL OF APPLIED PHYSICS 47 2 1422 - 1425 2008年02月 [査読有り][通常論文]
   

  Dielectric phase transition of epitaxial films of antiferroelectric squaric acid (SQ) with nanometer-order thickness was detected from the sample current measurement during reflection high-energy electron diffraction (RHEED) observation. The current changed markedly when the sample temperature was increased continuously. This phenomenon can be explained by considering the energy required to accommodate a charge in a molecule embedded on the surface of a dielectric, which is related to the phase transition in thin films through dielectric relaxation. The onset temperature was dependent on the substrate materials and film thickness, which indicates that the dielectric transition temperature is affected by epitaxial strain effects.
• Magnetotransport properties of Fe/pentacene/Co : TiO2 junctions with Fe top contact electrodes prepared by thermal evaporation and pulsed laser deposition

  Toshihiro Shimada, Hiroyuki Nogawa, Takuya Noguchi, Yutaka Furubayashi, Yukio Yamamoto, Yasushi Hirose, Taro Hitosugi, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS 47 2 1184 - 1187 2008年02月 [査読有り][通常論文]
   

  We fabricated heterojunctions using organic semiconductor pentacene sandwiched between two different magnetic electrodes: Co-doped TiO2 (Co:TiO2) and Fe. The conductance of the junctions was measured as a function of magnetic field. We found that the characteristics of the junctions are strongly dependent on the method used to deposit the Fe top electrode on pentacene. The magnetotransport properties can be explained by the effect of the interface morphology and spin polarization of interface traps.
• Femtosecond depolarization dynamics of tris(8-hydroxyquinoline) aluminum films

  N. Ogawa, A. Miyata, H. Tamaru, T. Suzuki, T. Shimada, T. Hasegawa, K. Saiki, K. Miyano

  CHEMICAL PHYSICS LETTERS 450 4-6 335 - 339 2008年01月 [査読有り][通常論文]
   

  For vapor-deposited tris(8-hydroxyquinoline) aluminum thin films, steady-state and subpicosecond transient optical anisotropy are investigated. It is found that the transient absorption anisotropy decays within tens of picoseconds. With a simple model calculation, the excited state population and anisotropy decay dynamics are disentangled, and the latter signal, the depolarization of the excited state, is explained by the energy transfer between the non-orthogonally-coordinated quinolate ligands. It is also shown that there are two pathways for this fast interligand energy transfer. (c) 2007 Elsevier B.V. All rights reserved.
• Heteroepitaxial growth of ferromagnetic rutile CoxTi1-xO2-delta on GaN(0001)

  Yasushi Hirose, Taro Hitosugi, Junpei Kasai, Yutaka Furubayashi, Kiyomi Nakajima, Toyohiro Chikyow, Seiji Konuma, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS LETTERS 92 4 042503  2008年01月 [査読有り][通常論文]
   

  A rutile CoxTi1-xO2-delta (100) film was heteroepitaxially grown on GaN (0001) by pulsed laser deposition. Magneto-optical Kerr effect and cross-sectional transmission electron microscope (TEM) measurements revealed that Co0.03Ti0.97O2-delta films prepared at an oxygen partial pressure of 10(-6)-10(-5) Torr with a carrier density n(e)>= 3x10(18) cm(-3) exhibit room-temperature ferromagnetism without any precipitates or secondary phase. High-resolution TEM observations confirmed that the interface between CoxTi1-xO2-delta and GaN is atomically smooth without intermixing. These results lead us to conclude that CoxTi1-xO2-delta is promising as a spin injector in GaN-based spin-electronic devices. (c) 2008 American Institute of Physics.
• Ferromagnetic rutile CoxTi1-xO2-delta heteroepitaxy on wurtzite GaN and ZnO

  Hirose Yasushi, Hitosugi Taro, Kasai Junpei, Furubayashi Yutaka, Nakajima Kiyomi, Chikyow Toyohiro, Konuma Seiji, Shimada Toshihiro, Hasegawa Tetsuya

  PHYSICA STATUS SOLIDI C - CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 5, NO 9 5 9 3104 - + 2008年 [査読有り][通常論文]
   

  Rutile CoxTi1-xO2-δ (100) films were heteroepitaxially grown on GaN (0001) and ZnO (0001) by pulsed laser deposition. Magneto-optical Kerr effect measurements indicated that the Co xTi1-xO2-δ films grown at appropriate oxygen partial pressure show room-temperature ferromagnetism both on GaN (0001) and ZnO (0001) substrate. XRD and cross-sectional TEM measurements confirmed solid solution of Co in rutile TiO2 matrix without any precipitates and secondary phases. High-resolution TEM observation of the Co xTi1-xO2-δ/GaN interface revealed atomically smooth interface without intermixing, which promises the application of CoxTi1-xO2-δ in opto-spintronics devices as a spin injector. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.
• Oriented film growth of organic semiconductor sexithiophene on artificial periodic grooves and electrical conduction properties of the films

  S. Ikeda, Y. Wada, K. Inaba, K. Terashima, T. Shimada, K. Saiki

  Materials Research Society Symposium Proceedings 1059 KK11-11  2008年 [査読有り][通常論文]
   

  ABSTRACT Film growth of organic semiconductor α-sexithiophene (6T) was studied using substrates with artificial periodic grooves. The grooves were fabricated on thermally oxidized silicon substrates by electron beam lithography. Based on the orientation analysis by atomic force microscopy and grazing-incidence x-ray diffraction, part of the 6T grains grew having the in-plane orientational relationship with the artificial grooves. This phenomenon corresponds to “ggraphoepitaxy” which has been well known in inorganic materials research field. As well as the in-plane preferred orientation, one-dimensional structure consisting of connected 6T grains was observed. The electrical conduction properties of the films were also evaluated.
• Quantitative analysis of thin-film conductivity by scanning microwave microscope

  Sohei Okazaki, Noriaki Okazaki, Yasushi Hirose, Yutaka Furubayashi, Taro Hitosugi, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED SURFACE SCIENCE 254 3 757 - 759 2007年11月 [査読有り][通常論文]
   

  We propose a novel method for high-throughput quantitative analysis of thin-film conductivity sigma by using a scanning microwave microscope (S mu M). We demonstrated that composition spread thin films of Ti(1-x)Nb(x)O(2) can be utilized as a standard reference in a wide s range. The shift in Q-value measured by SmM along the composition-spread axis showed a single peak, which moved to the lower x side with film thickness. This behavior was confirmed by electrical field simulation using the finite element method. (C) 2007 Published by Elsevier B.V.
• Anatase phase stability and doping concentration dependent refractivity in codoped transparent conducting TiO2 films

  T. L. Chen, Y. Furubayashi, Y. Hirose, T. Hitosugi, T. Shimada, T. Hasegawa

  JOURNAL OF PHYSICS D-APPLIED PHYSICS 40 19 5961 - 5964 2007年10月 [査読有り][通常論文]
   

  Nb0.06Sn x Ti0.94-x O-2 ( x <= 0.3) thin films were grown by a pulsed-laser deposition method with varying Sn concentration. Through a combinatorial technique, we find that Sn concentration can reach a maximum of about x = 0.3 while maintaining the stable anatase phase and epitaxy. A doping concentration dependence of the refractivity is revealed, in which refractivity reduction at a wavelength of. = 500 nm is estimated to be 12.4% for Nb0.06Sn0.3Ti0.64O2 thin film. Sn doping induced band-gap blue shift can be contributed to the mixing of extended Sn 5s orbitals with the conduction band of TiO2. Low resistivity on the order of 10(-4) Omega cm at room temperature and high internal transmittance of more than 95% in the visible light region are exhibited for Nb0.06Sn x Ti0.94-x O2 thin films ( x <= 0.2). Optical and transport analyses demonstrate that doping Sn into Nb0.06Ti0.94O2 can reduce the refractivity while maintaining low resistivity and high transparency.
• Correlation between gap states and off-current in pentacene field-effect transistors observed by sub-band-gap photocurrent-voltage measurement

  Manabu Ohtomo, Toshihiro Shimada, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 46 33-35 L817 - L819 2007年09月 [査読有り][通常論文]
   

  We report the correlation between sub-band-gap photocurrent and various device parameters of polycrystalline pentacene field-effect transistors. It was revealed that we can estimate various device characteristics including the origin of photocarriers and the density of gap states by changing the gate bias and drain voltage during the photocurrent measurement. In our experiment, carrier mobility was not related to photocurrent in the sub-band-gap region, even though a large photocurrent implies a large number of trapping states. The off-current obviously correlates with the photocurrent, suggesting that the origin of the off-currents is the gap states widely distributed near the valence band edge.
• Metal-induced Urbach tail at the gold/pentacene interface of top-contact organic field effect transistors

  Manabu Ohtomo, Toshihiro Shimada, Koichiro Saiki, Tetsuya Hasegawa

  JOURNAL OF APPLIED PHYSICS 102 6 064510  2007年09月 [査読有り][通常論文]
   

  We investigated the photocurrent-voltage characteristics of pentacene field effect transistors in order to study the gap state distribution and carrier generation mechanism. In top-contact devices, the photocurrent spectrum versus photon energy exhibited the typical Urbach tail, while such a tail was not observed in bottom-contact devices. The formation of this Urbach tail can be explained by assuming that diffused gold nanoparticles at the gold/pentacene interface cause microfields and stabilize the excitons. This mechanism also provides an explanation for the reduced barrier height and Ohmic contact formation at "dirty" interfaces fabricated by metal deposition.
• Fabrication of low resistivity Nb-doped TiO2 transparent conductive polycrystalline films on glass by reactive sputtering

  Naoomi Yamada, Taro Hitosugi, Ngoc Lam Huong Hoang, Yutaka Furubayashi, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS 46 8A 5275 - 5277 2007年08月 [査読有り][通常論文]
   

  Nb-doped anatase TiO2 (TNO) polycrystalline films with excellent conductivity and transparency were successfully fabricated by reactive sputtering combined with post annealing in H-2 gas. The H-2 annealing of as-deposited amorphous films caused an abrupt decrease in resistivity (p), which was accompanied by crystallization into the anatase structure. A film deposited on an unheated glass substrate with subsequent H2 annealing at 600 degrees C exhibited a resistivity of 9.5 x 10(-4) Omega cm and an average optical transmittance of similar to 75% in the visible region. This p value is of the same order as that of epitaxial TNO films, which indicates that sputtering is a promising technique for obtaining large-area TNO films.
• Analysis of charge transport in a polycrystalline pentacene thin film transistor by temperature and gate bias dependent mobility and conductance

  Dong Guo, Tetsuhiko Miyadera, Susumu Ikeda, Toshihiro Shimada, Koichiro Saiki

  JOURNAL OF APPLIED PHYSICS 102 2 023706  2007年07月 [査読有り][通常論文]
   

  The gate bias and temperature dependent field-effect mobility and conductance of a polycrystalline pentacene thin film transistor (TFT) were analyzed to study the charge transport in the material. Since both heating and cooling can obviously change the film morphology, a relatively narrow temperature range was adopted to rule out the possible influence of structure variation on the device characterization. Both mobility and conductance values increased with the gate bias and showed a thermally activated Arrhenius-like behavior, while the threshold voltage deceased with temperature. Several models were compared, and it was found that the observations could only be well interpreted by a multiple trapping model, which suggests that the temperature and gate bias dependences should be attributed to the increased free charge carrier density. The density of trap states in the band gap was evaluated by the field-effect mobility as well as the field-effect conductance data. The results disclose a possible field-effect mobility much higher than the present record in a polycrystalline pentacene TFT. (C) 2007 American Institute of Physics.
• Wetting-dewetting oscillations of liquid films during solution-mediated vacuum deposition of rubrene

  Yui Ishii, Toshihiro Shimada, Noriaki Okazaki, Tetsuya Hasegawa

  LANGMUIR 23 12 6864 - 6868 2007年06月 [査読有り][通常論文]
   

  We found a novel oscillating phenomenon associated with surface wetting during the vacuum deposition of an organic semiconductor (rubrene) on a liquid film (bis(2-ethylhexyl)sebacate, B2EHS). In-situ observations by an optical microscope revealed that the oscillation was associated with the growth of the rubrene crystals. The oscillation frequency was proportional to the evaporation rate of rubrene. On the basis of the contact angle measurements, it was concluded that the oscillation is probably due to the change in the contact angle of the liquid caused by the formation of ultrathin rubrene films on the liquid surface.
• Wetting-dewetting oscillations of liquid films during solution-mediated vacuum deposition of rubrene

  Yui Ishii, Toshihiro Shimada, Noriaki Okazaki, Tetsuya Hasegawa

  LANGMUIR 23 12 6864 - 6868 2007年06月 [査読有り][通常論文]
   

  We found a novel oscillating phenomenon associated with surface wetting during the vacuum deposition of an organic semiconductor (rubrene) on a liquid film (bis(2-ethylhexyl)sebacate, B2EHS). In-situ observations by an optical microscope revealed that the oscillation was associated with the growth of the rubrene crystals. The oscillation frequency was proportional to the evaporation rate of rubrene. On the basis of the contact angle measurements, it was concluded that the oscillation is probably due to the change in the contact angle of the liquid caused by the formation of ultrathin rubrene films on the liquid surface.
• Visualization of induced charge in an organic thin-film transistor by cross-sectional potential mapping

  S Ikeda, T Shimada, T Kiguchi, M, Saiki, K

  J. Appl. Phys. 101 9 094509 - 94509 American Institute of Physics 2007年05月 [査読有り][通常論文]
   

  Kelvin probe force microscopy was applied to the cross-sectional potential imaging of a working organic thin-film transistor (OTFT). The bottom-contact-type OTFT with an active layer of copper-phthalocyanine (CuPc) was cleaved and internal potential distribution of its channel region was visualized. The potential distribution on the cross section changed depending on the applied drain and gate voltage. Horizontal potential distribution in the semiconductor film from source to drain direction was roughly consistent with the results of surface potential imaging previously reported. Vertical potential distribution from bottom (gate) to top (CuPc film) showed that a potential peak appeared along the semiconductor/insulator interface when a negative voltage was applied to the gate. The charge injection process is discussed based on the visualized potential peak at the interface. ©2007 American Institute of Physics
• Transport properties of d-electron-based transparent conducting oxide: Anatase Ti1-xNbxO2

  Yutaka Furubayashi, Naoomi Yamada, Yasushi Hirose, Yukio Yamamoto, Makoto Otani, Taro Hitosugi, Toshihiro Shimada, Tetsuya Hasegawa

  JOURNAL OF APPLIED PHYSICS 101 9 093705  2007年05月 [査読有り][通常論文]
   

  The transport properties of a d-electron-based transparent conducting oxide, Nb-doped anatase Ti1-xNbxO2, were investigated as a function of the Nb content x. From optical resistivity spectra, the static effective mass was evaluated to be similar to 0.4m(0) in the low-carrier-concentration (n(e)) regime, which is approximately the same as those of conventional transparent conducting oxides (TCOs), and two orders of magnitude smaller than that reported for rutile TiO2. The Hall mobility at room temperature, which is maximized at around x=0.01 (n(e)similar to 10(21) cm(-3)), was found to be mainly dominated by optical phonon scattering unlike that of other TCOs. (c) 2007 American Institute of Physics.
• Fabrication of highly conductive Ti1-xNbxO2 polycrystalline films on glass substrates via crystallization of amorphous phase grown by pulsed laser deposition

  T. Hitosugi, A. Ueda, S. Nakao, N. Yamada, Y. Furubayashi, Y. Hirose, T. Shimada, T. Hasegawa

  APPLIED PHYSICS LETTERS 90 21 212106  2007年05月 [査読有り][通常論文]
   

  Nb-doped anatase TiO2 [Ti0.94Nb0.06O2 (TNO)] films with high electrical conductivity and transparency were fabricated on nonalkali glass using pulsed laser deposition and subsequent annealing in a H-2 atmosphere. The amorphous films as deposited on unheated substrates were found to crystallize, forming polycrystalline films at around 350 degrees C. The films annealed at 500 degrees C showed resistivity down to 4.6x10(-4) Omega cm at room temperature and optical transmittance of 60%-80% in the visible region, which are comparable to those of epitaxial films. These results indicate that TNO films have the potential to be practical transparent conducting oxides that could replace indium tin oxide. (c) 2007 American Institute of Physics.
• Electron energy loss spectroscopy of ultrathin pentacene field effect transistors

  Toshihiro Shimada, Koichiro Saiki

  JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA 154 3 119 - 122 2007年02月 [査読有り][通常論文]
   

  Electron energy loss spectra of ultrathin pentacene field effect transistors were measured by applying gate bias voltages. Tailing and shouldering of the primary peak on the energy loss side was observed for 1.5 nm thick films when a negative gate bias was applied. The energy loss spectra obtained from the deconvolution of the primary electron profile showed peaks, and the peak energies increased as a function of the gate bias voltage. This is consistent with the behavior of two-dimensional plasmons of field-induced carriers. The thickness dependence is explained by the thickness of the accumulation layer and the probing depth of the spectroscopy. (c) 2007 Elsevier B.V. All rights reserved.
• Fabrication of TiO2-based transparent conducting oxide films on glass by pulsed laser deposition

  Taro Hitosugi, Atsuki Ueda, Yutaka Furubayashi, Yasushi Hirose, Seiji Konuma, Toshihiro Shimada, Tetsuya Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 46 1-3 L86 - L88 2007年01月 [査読有り][通常論文]
   

  Nb-doped anatase TiO2 (Ti0.94Nb0.06O2) films with excellent conductivity and transparency were deposited on non-alkali glass by pulsed laser deposition. X-ray diffraction analysis and transmission electron microscopy confirmed that the obtained films were polycrystalline with anatase structure. The films deposited at a substrate temperature of 250 degrees C with subsequent H-2 annealing at 500 degrees C showed a resistivity of 1.5 x 10(-3) Omega(.)cm at room temperature and an optical transmittance of 60-80% in the visible region. These results indicate that anatase Ti0.94Nb0.06O2 has great potential as a transparent conducting oxide that could replace Sn-doped In2O3 (ITO).
• Orientation control of standing epitaxial pentacene monolayers using surface steps and in-plane band dispersion analysis by angle resolved photoelectron spectroscopy

  T. Suzuki, T. Shimada, K. Ueno, S. Ikeda, K. Saiki, T. Hasegawa

  Materials Research Society Symposium Proceedings 965 0965-S06-19  2007年 [査読有り][通常論文]
   

  ABSTRACT We prepared quasi single crystalline pentacene monolayer films on Bi-terminated Si(111) by using bunched steps on vicinally-cut surfaces as an orientation template. Band dispersion in the conduction plane of pentacene was clearly observed by angle-resolved photoelectron spectroscopy.
• Post-processing of spin-coated organic thin films in solvent vapors: Vapor pressure monitoring by infrared absorption and the effect of electric fields

  Toshihiro Shimada

  THIN SOLID FILMS 515 4 1568 - 1572 2006年12月 [査読有り][通常論文]
   

  We have examined the effect of the post-processing of spin-coated tetracene and DAST (4'-dimethylamino-N-methyl-4-stilbazolium tosylate) films in their solvent vapor to examine the possibility of precisely controlling the vapor pressure and studying the effect of applying electric fields to their structural properties. It was demonstrated that the solvent concentration in the vapor phase can be monitored by infrared spectroscopy. The thickness uniformity of the tetracene films was improved by the formation of a mixture of the tetracene crystals with the saturated solution ("solution ultrathin film") on the surface. Crystals with an ordered orientation were obtained by additionally applying an electric field during the vapor exposure of the DAST. The present technique for monitoring the solvent vapor pressure is also applicable for controlling the drying speed during the inkjet printing of functional organic materials. (c) 2006 Elsevier B.V. All rights reserved.
• Pulsed molecular beam scattering of a planar-shaped organic molecule on regularly stepped surfaces of hydrogen-terminated Si(111)

  Toshihiro Shimada, Hisashi Ichikawa, Koichiro Saiki

  APPLIED PHYSICS LETTERS 89 14 141902  2006年10月 [査読有り][通常論文]
   

  Strong dependence of surface residence time of a planar organic molecule (hydrogen phthalocyanine) on vicinal surfaces of hydrogen-terminated Si(111) was observed in pulsed molecular beam scattering experiments. These results can be explained by the difference in the microscopic contact area of the molecules on the surface, which determines the binding force between the migrating molecules and the surface. The relationship between the observed behavior and the organic thin film growth is discussed. (c) 2006 American Institute of Physics.
• Interaction between surface migrating pentacene molecules and chemically modified surfaces of silicon oxides studied by pulsed molecular beam scattering

  H. Ichikawa, A. Koma, K. Saiki, T. Shimada

  SURFACE SCIENCE 600 17 L236 - L239 2006年09月 [査読有り][通常論文]
   

  The interaction between pentacene molecules and organic self-assembling monolayers formed on silicon oxides (SiO2) was studied by measuring the surface scattering time profile of the pulsed molecular beam of pentacene. It was found that the surface residence time (SRT) of pentacene was significantly reduced on a surface treated with hexamethyl silazarane (HMDS) compared with that on a bare SiO2 surface. The activation energies derived from the temperature dependence of the SRT were 24 kJ/mol and 100 kJ/mol for HMDS-SiO2 and the bare SiO2, respectively. A surface treated with octadecyltrichlorosilane (OTS) showed SRT values almost the same as those on the bare SiO2 surface, which was due to exposed SiO2 regions on the thermally-degraded OTS-SiO2. The growth mechanism with improved quality is due to the shallower adsorption potential and enhanced migration of pentacene by the surface alkylation. (c) 2006 Elsevier B.V. All rights reserved.
• Graphoepitaxy of sexithiophene on thermally oxidized silicon surface with artificial periodic grooves

  Susumu Ikeda, Koichiro Saiki, Ken Tsutsui, Tomohiko Edura, Yasuo Wada, Hiroyuki Miyazoe, Kazuo Terashima, Katsuhiko Inaba, Toru Mitsunaga, Toshihiro Shimada

  APPLIED PHYSICS LETTERS 88 25 251905  2006年06月 [査読有り][通常論文]
   

  Graphoepitaxial growth of a sexithiophene (6T) thin film was achieved on a thermally oxidized silicon surface with artificial periodic grooves. The surface structure was fabricated by electron beam lithography and the thin film was grown by molecular beam deposition. A well-pronounced, in-plane oriented component ([010](6T)parallel to grooves) was identified by grazing incidence x-ray diffraction, though there also existed some randomly oriented 6T grains. Presence of the graphoepitaxial component was also confirmed by results of the orientational analysis of atomic force microscopy images. It was shown that the in-plane orientation control of organic semiconductors is possible using graphoepitaxy. (c) 2006 American Institute of Physics.
• Intrinsic Faraday spectra of ferromagnetic rutile Ti1-xCoxO2-delta

  Yasushi Hirose, Taro Hitosugi, Yutaka Furubayashi, Go Kinoda, Kazuhisa Inaba, Toshihiro Shimada, Tetsuya Hasegawa

  APPLIED PHYSICS LETTERS 88 25 252508  2006年06月 [査読有り][通常論文]
   

  We have investigated the Faraday spectra of ferromagnetic rutile Ti1-xCoxO2-delta films grown on Al2O3 (0001). The Faraday spectra strongly depended on the film thickness, revealing the significant effect of the multiple reflections of light. The intrinsic Faraday spectra of rutile Ti1-xCoxO2-delta were corrected for this multiple reflection effect on the basis of an optical model and compared with the absorption spectra in detail. The quantitatively good correspondence between intrinsic Faraday ellipticity and optical band edge strongly suggests that rutile Ti1-xCoxO2-delta is an intrinsic ferromagnetic semiconductor. The exchange parameters, N-0 alpha and N-0 beta, were estimated as the order of similar to 0.1 eV. (c) 2006 American Institute of Physics.
• Enhancement of magneto-optical properties of anatase Co : TiO2 Co-doped with Nb

  G Kinoda, T Hitosugi, Y Yamamoto, Y Furubayashi, K Inaba, Y Hirose, T Shimada, T Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45 12-16 L387 - L389 2006年04月 [査読有り][通常論文]
   

  We have fabricated Ti0.95-xNbxCo0.05O2 thin films by the pulsed laser deposition technique. Carrier density was found to be almost identical to the Nb concentration up to x = 0.06, indicating that doped Nb atoms generate carriers with > 80% efficiency. In this doping range, magneto-optical properties were significantly enhanced by Nb-doping. The remanent Faraday rotation at a wavelength of 405 nm was as high as 5.6 x 10(3) deg/cm, which is approximately one order of magnitude higher than that of a film free of Nb-doping. The present results support the hypothesis that conduction electrons play an essential role in the ferromagnetism of Co-doped TiO2.
• Carrier induced ferromagnetism in Nb doped Co : TiO2 and Fe : TiO2 epitaxial thin film

  T Hitosugi, G Kinoda, Y Yamamoto, Y Furubayashi, K Inaba, Y Hirose, K Nakajima, T Chikyow, T Shimada, T Hasegawa

  JOURNAL OF APPLIED PHYSICS 99 8 08M121  2006年04月 [査読有り][通常論文]
   

  We have investigated the carrier induced magnetic properties of anatase Ti1-x-yNbxMyO2 (M=Co,Fe) epitaxial films grown by the pulsed laser deposition technique. For Ti0.95-xNbxCo0.05O2, the n-type carrier density could be controlled in a wide range (4.9x10(17) cm(-3) to 2.7x10(21) cm(-3)) by Nb doping (x=0-0.2). The temperature dependence of the resistivity showed metallic behavior, suggesting that Ti0.95-xNbxCo0.05O2 undergoes a semiconductor to metal transition along with a slight carrier doping less than x < 0.03. In both Co-doped and Fe-doped films, we have confirmed hysteresis in M-H curves, and the anomalous Hall effect at room temperature. This strongly suggests that the charge carriers are spin polarized and mediate ferromagnetic interaction between local spins on transition metal ions. In the case of Ti0.94-xNbxFe0.06O2, ferromagnetism is sensitive to carrier concentration. That is, the x=0.002 film is nonmagnetic even at 3 K, while room-temperature ferromagnetism appears at x=0.01. (C) 2006 American Institute of Physics.
• Novel transparent conducting oxide: Anatase Ti1-xNbxO2

  Y Furubayashi, T Hitosugi, Y Yamamoto, Y Hirose, G Kinoda, K Inaba, T Shimada, T Hasegawa

  THIN SOLID FILMS 496 1 157 - 159 2006年02月 [査読有り][通常論文]
   

  Single-crystalline Ti1-xNbxO2 (x = 0.2) films of 40 nm thickness were deposited on SrTiO3 (100) substrates by the pulsed laser deposition (PLD) technique. X-ray diffraction measurement confirmed epitaxial growth of anatase (001) film. The resistivity of Ti1-xNbxO2 films with x >= 0.03 is 2-3 x 10(-4) Omega cm at room temperature. The carrier density of Ti1-xNbxO2, which is almost proportional to the Nb concentration, can be controlled in a range of 1 x 10(19) to 2 x 10(21) cm(-3). Optical measurements revealed that internal transmittance in the visible and near-infrared region for films with x <= 0.03 was more than 97%. These results demonstrate that the presently developed anatase Ti1-xNxO2 is one of the promising candidates for the practical TCOs. (c) 2005 Elsevier B.V. All rights reserved.
• Magnetic properties of rutile Ti1-xFexO2 epitaxial thin films

  K Inaba, T Hitosugi, Y Hirose, Y Furubayashi, G Kinoda, Y Yamamoto, TW Kim, H Fujioka, T Shimada, T Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 45 4-7 L114 - L116 2006年02月 [査読有り][通常論文]
   

  Growth conditions for pulsed laser deposition of ferromagnetic Ti1-xFexO2 films with the rutile structure have been optimized on the basis of magnetooptical Kerr effect (MOKE) measurements. Thus, it was found that Ti0.94Fe0.06O2 films prepared under very limited growth conditions, at a substrate temperature of 650-675 degrees C and an oxygen pressure of similar to 1 x 10(-6) Torr, show ferromagnetism at room temperature. The optimized films revealed a saturation magnetization of 1.3 mu(B) and a coercive field of 0.14 kOe. From XPS measurements, the valence state of Fe was determined to be 3+, ruling out the possibility that ferromagnetism may arise from Fe3O4 nanoparticles.
• Development of high-throughput combinatorial terahertz time-domain spectrometer and its application to ternary composition-spread film

  M. Ohtani, T. Hitosugi, Y. Hirose, J. Nishimura, A. Ohtomo, M. Kawasaki, R. Inoue, M. Tonouchi, T. Shimada, T. Hasegawa

  Applied Surface Science 252 7 2622 - 2627 2006年01月21日 [査読有り][通常論文]
   

  We have developed a high-throughput combinatorial terahertz (THz) time-domain spectrometer (CTTDS) and applied to a ternary composition-spread film. This technique has possibilities to reveal a variety of physical properties such as complex refractive index, complex dielectric constant, and complex electrical conductivity. Further, this method is a non-contact and non-destructive way to map those physical properties. The demonstration of THz transmittance mapping of ternary composition-spread film, with a spatial resolution of 1 mm, reveals metallic behavior in specific range of film compositions. This prospective technique may serve as a convenient tool for the high-throughput, non-contact, non-destructive, and spatially resolved characterization suited for combinatorial composition-spread films. © 2005 Elsevier B.V. All rights reserved.
• Thickness dependent characteristics of a copper phthalocyanine thin-film transistor investigated by in situ FET measurement system

  Ikeda, S Yamakawa, H Kiguchi, M Nakayama, M Saiki, T Shimada, T Miyadera, T Tsutsui, K, Wada, Y

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS 455 347 - 351 2006年 [査読有り][通常論文]
  
• Electron spectroscopy of dye-sensitized anatase(001) surfaces under illumination

  T Shimada, T Kaji, T, Saiki, K

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS 455 317 - 325 2006年 [査読有り][通常論文]
  
• Development of UHV-LT MFM operating in magnetic field

  Hidetaka Sugaya, Taro Hitosugi, Toshihiro Shimada, Toshihiko Nagamura, Yuji Matsumoto, Tetsuya Hasegawa

  AIP Conference Proceedings 850 1667 - 1668 2006年 [査読有り][通常論文]
   

  We have developed an ultrahigh-vacuum low-temperature magnetic force microscope (UHV-LT MFM) which can operate in magnetic fields. The microscope is based on a non-contact atomic force microscope using a piezoelectric cantilever. Measurements of hard disc media confirmed spatial resolution of ∼50 nm even at low temperatures down to 10 K. The maximum scanning area is as wide as 2.5 μm × 2.5 μm at 10 K and 7.5 μm × 7.5 μm at room temperature. We have also equipped the microscope with an electromagnet in order to apply external magnetic fields up to 0.25 T in the horizontal direction. The MFM head is mounted on a piezo-driven rotation stage, so that the direction of magnetic field relative to the sample surface can be set arbitrarily. © 2006 American Institute of Physics.
• 30aUE-7 Bi2212の低温磁場下STM/STS観察III(30aUE 磁束量子系(磁束電子構造),領域8(強相関系:高温超伝導,強相関f電子系など))

  福尾 則学, 眞嶋 秀樹, 一杉 太郎, 島田 敏宏, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

  日本物理学会講演概要集 61 0 648 - 648 一般社団法人 日本物理学会 2006年 [査読有り][通常論文]
  
• 24aPS-84 Bi2212の低温磁場下STM/STS観察IV(24aPS 領域8ポスターセッション(低温),領域8(強相関系:高温超伝導,強相関f電子系など))

  福尾 則学, 一杉 太郎, 島田 敏宏, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

  日本物理学会講演概要集 61 0 459 - 459 一般社団法人 日本物理学会 2006年 [査読有り][通常論文]
  
• Electron spectroscopy of dye-sensitized anatase(001) surfaces under illumination

  Toshihiro Shimada, Toshihiko Kaji, Koichiro Saiki

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS 455 317 - 325 2006年 [査読有り][通常論文]
   

  Dye-sensitized anatase TiO2 (001) surface was prepared in the solution directly connected with an ultrahigh vacuum analysis chamber. We measured the ultraviolet photoelectron spectroscopy (UPS) and low energy electron transmission (LEET) of the dye-sensitized surfaces with and without illumination. The highest occupied molecular orbital (HOMO) and other levels showed different peak shifts in UPS when illuminated. The observations were discussed in relation to the device characteristics of a half photocell.
• Thickness dependent characteristics of a copper phthalocyanine thin-film transistor investigated by in situ FET measurement system

  Susumu Ikeda, Hidemitsu Yamakawa, Manabu Kiguchi, Manabu Nakayama, Koichiro Saiki, Toshihiro Shimada, Tetsuhiko Miyadera, Ken Tsutsui, Yasuo Wada

  MOLECULAR CRYSTALS AND LIQUID CRYSTALS 455 347 - 351 2006年 [査読有り][通常論文]
   

  The influence of active layer thickness on transport characteristics of a copper phthalocyanine thin-film transistor was investigated by using the in situ FET measurement system with the film deposition continued up to several hundred nm in thickness. The drain current and mobility showed maximum values in the early stage of film growth and then decreased with the increasing film thickness. This result suggests that the over-grown layer affects the transport characteristics of the conductive accumulation layer, for example, owing to change of the electric field in the device.
• Correlation between vortex distribution and electronic inhomogeneity in Bi2Sr2CaCu2O8+delta as probed by STM/STS

  Fukuo Noritaka, Mashima Hideki, Kinoda Go, Hitosugi Taro, Shimada Toshihiro, Shimizu Keisuke, Shimoyama Jun-ichi, Kishio Kohji, Matsumoto Yuji, Hasegawa Tetsuya

  LOW TEMPERATURE PHYSICS, PTS A AND B 850 797 - + 2006年 [査読有り][通常論文]
  
• Scanning tunneling microscopy/spectroscopy of heavily overdoped Bi2Sr2CuOy single crystals

  Hideki Mashima, Noritaka Fukuo, Go Kinoda, Taro Hitosugi, Toshihiro Shimada, Takeshi Kondo, Yoshinori Okada, Hiroshi Ikuta, Yuji Matsumoto, Tetsuya Hasegawa

  LOW TEMPERATURE PHYSICS, PTS A AND B 850 509 - + 2006年 [査読有り][通常論文]
   

  We have carried out scanning tunneling microscopy/spectroscopy (STM/STS) of heavily overdoped Bi2Sr2CuOy single crystals with T-c < 2 K. STS spectra showed a pseudogap structure with dull coherence peaks. Furthermore, we found that the magnitude of pseudogap is spatially non-uniform in a nm scale and varies from 10 to 30 meV. This supports a scenario that the electronic inhomogeneity is a consequence of randomly distributed Coulomb potential in the CuO2 layers induced by disorder of excess oxygen in the BiO layers.
• 有機分子のエピタキシャル薄膜成長における光励起の影響(<小特集>有機結晶の新展開)

  島田 敏宏

  日本結晶成長学会誌 32 5 347 - 352 日本結晶成長学会 2005年12月31日 [査読無し][通常論文]
   

  低分子の結晶性有機半導体薄膜は,トランジスタ等への応用が期待されており,結晶性・配向性を高める方法が探索されている.そのひとつとして,蒸着中に分子・薄膜を光励起する実験を行っている.励起状態の寿命が長く,光重合することが知られているC_<60>をMoS_2(0001)上に成長した場合と,有機ELに用いられ大きな静的双極子モーメントを持つ極性分子であるAlq3をKCl(001)上に成長した場合についての結果を紹介する.C_<60>については,光強度に対して閾値をもって核形成頻度が上昇した.また,第1層目の縁にそって第2層目が成長するという,光照射がない場合と異なる成長形態が見られた.Alq3については,照射するレーザーの偏光方向と平行に配向した針状結晶が成長することが見出された.
• Bulk-like pentacene epitaxial films on hydrogen-terminated Si(111)

  T Shimada, H Nogawa, T Hasegawa, R Okada, H Ichikawa, K Ueno, K Saiki

  APPLIED PHYSICS LETTERS 87 6 061917  2005年08月 [査読有り][通常論文]
   

  The epitaxial growth of pentacene on hydrogen-terminated Si(111) is reported. Reflection high energy electron diffraction (RHEED) revealed that the crystal packing resembles that in the bulk crystal even at a monolayer thickness, which was maintained in multilayers. A ripening effect was clearly observed by atomic force microscopy (AFM). These results are important to obtain oriented crystalline films of pentacene combined with silicon microdevices with reduced defect densities. (c) 2005 American Institute of Physics.
• Electron spectroscopy of organic thin-film FETs

  Toshihiro Shimada

  Electrical Engineering in Japan (English translation of Denki Gakkai Ronbunshi) 152 1 31 - 36 2005年07月15日 [査読有り][通常論文]
   

  Organic thin-film FETs have been studied by using electron spectroscopic techniques. Ultraviolet photoelectron spectroscopy has revealed that photopolymerization is enhanced by fabricating FET structure. Energy levels and the effective mass of charge carriers are discussed based on the results of photoelectron spectroscopy and electron energy loss spectroscopy. © 2005 Wiley Periodicals, Inc.
• 変調分子線を用いた有機薄膜蒸着基礎過程の解明

  島田 敏宏

  表面科学 = Journal of The Surface Science Society of Japan 26 7 410 - 414 日本表面科学会 2005年07月10日 [査読無し][通常論文]
   

  Interaction between molecules and surfaces and nucleation processes during organic thin film growth have been studied by modulated molecular beam experiments. After a brief introduction of the background and the experimental technique, we describe the results of our study on the interaction between pentacene and chemically modified SiO₂ surfaces. Molecular migration on regularlly-stepped vicinal surfaces of silicon and crystal nucleation controlled by pulsed supply of the molecules are discussed on the basis of the experimental data on phthalocyanine and quinacridone.
• A transparent metal: Nb-doped anatase TiO2

  Y Furubayashi, T Hitosugi, Y Yamamoto, K Inaba, G Kinoda, Y Hirose, T Shimada, T Hasegawa

  APPLIED PHYSICS LETTERS 86 25 252101  2005年06月 [査読有り][通常論文]
   

  This Letter focuses on the discovery of a transparent conducting oxide (TCO), anatase Ti1-xNbxO2 films with x=0.002-0.2. The resistivity of films with x >= 0.03 is 2-3x10(-4) Omega cm at room temperature. The carrier density of Ti1-xNbxO2 can be controlled in a range of 1x10(19) to 2x10(21) cm(-3). The internal transmittance for films with x <= 0.03 (40 nm thickness) is about 97% in the visible light region. The transport and optical parameters are comparable to those of typical TCOs, such as In2-xSnxO3 and ZnO. (c) 2005 American Institute of Physics.
• Electric-field-induced charge injection or exhaustion in organic thin film transistor

  M Kiguchi, M Nakayama, T Shimada, K Saiki

  PHYSICAL REVIEW B 71 3 035332  2005年01月 [査読有り][通常論文]
   

  The conductivity of organic semiconductors is measured in situ and continuously with a bottom contact configuration, as a function of film thickness at various gate voltages. The depletion layer thickness can be directly determined as a shift of the threshold thickness at which electric current began to flow. The in situ and continuous measurement can also determine qualitatively the accumulation layer thickness together with the distribution function of injected carriers. The accumulation layer thickness is a few monolayers and it does not depend on gate voltages. Rather it depends on the chemical species.
• Uniaxial alignment of Alq(3) by laser-assisted molecular beam epitaxy

  H Ichikawa, K Saiki, T Suzuki, T Hasegawa, T Shimada

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 46-49 L1469 - L1471 2005年 [査読有り][通常論文]
   

  The surface morphology of tris(8-hydroxyquinoline)aluminum (III) (Alq(3)) epitaxially grown on KCl(001) was drastically changed by a simultaneous blue laser irradiation during vacuum deposition. Needle-shaped microcrystals were aligned to the polarization direction of the laser, Parallel to the KCl[010] axis. The origin of alignment was discussed in comparison with the growth of non-polar organic molecular films, in which anisotropic heating played an important role.
• Heteroepitaxial growth of rutile TiO2 on GaN(0001) by pulsed laser deposition

  T Hitosugi, Y Hirose, J Kasai, Y Furubayashi, M Ohtani, K Nakajima, T Chikyow, T Shimada, T Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 50-52 L1503 - L1505 2005年 [査読有り][通常論文]
   

  Rutile TiO2(100) thin films have been grown on GaN(0001) surfaces by using the pulsed laser deposition method. Reflection high-energy electron diffraction (RHEED) measurements during the deposition clearly revealed the layer-by-layer growth of TiO2 at a substrate temperature of 400 C under an oxygen pressure of 1 x 10(-5) Torr. X-ray diffraction and atomic force microscopy confirmed that the obtained films have high crystallinity with atomically flat surfaces. Pole figure measurements revealed the epitaxial relationship between TiO2 and GaN, namely that the in-plane TiO2< 010 > axis aligns parallel to the GaN < 10 (1) over bar0 >.
• Ta-doped anatase TiO2 epitaxial film as transparent conducting oxide

  T Hitosugi, Y Furubayashi, A Ueda, K Itabashi, K Inaba, Y Hirose, G Kinoda, Y Yamamoto, T Shimada, T Hasegawa

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS & EXPRESS LETTERS 44 33-36 L1063 - L1065 2005年 [査読有り][通常論文]
   

  We present electrical transport and optical properties of Ta-doped TiO2 epitaxial thin films with varying Ta concentration grown by the pulsed laser deposition method. The Ti0.95Ta0.05O2 film exhibited a resistivity of 2.5 x 10(-4) Omega cm at room temperature, and an internal transmittance of 95% in the visible light region. These values are comparable to those of a Widely used transparent conducting oxide (TCO), indium tin oxide. Furthermore, this new material falls into a new category of TCOs that utilizes d electrons.
• 24pWA-3 Bi2212の低温磁場下STM/STS観察(高温超伝導(トンネル分光・輸送特性),領域8(強相関系:高温超伝導,強相関f電子系など))

  福尾 則学, 長谷川 哲也, 眞嶋 秀樹, 木野田 剛, 一杉 太郎, 島田 敏宏, 清水 圭輔, 下山 淳一, 岸尾 光二, 松本 祐司

  日本物理学会講演概要集 60 0 498 - 498 一般社団法人 日本物理学会 2005年 [査読有り][通常論文]
  
• 19aYH-6 Bi2212の低温磁場下STM/STS観察II(磁束量子系(相図・可視化・電子状態),領域8(強相関系 : 高温超伝導,強相関f電子系など))

  福尾 則学, 眞嶋 秀樹, 一杉 太郎, 島田 敏宏, 内田 智史, 下山 淳一, 岸尾 光二, 松本 祐司, 長谷川 哲也

  日本物理学会講演概要集 60 0 365 - 365 一般社団法人 日本物理学会 2005年 [査読有り][通常論文]
  
• Photoinduced change in the Raman spectrum of buckyferrocene ((Fe(C-60(CH3)(5))C5H5)

  T Shimada, Y Yamamoto, T Kaji, K Itaka, H Koinuma, Y Kuninobu, Y Matsuo, E Nakamura, K Saiki

  SOLID STATE COMMUNICATIONS 132 3-4 197 - 201 2004年10月 [査読有り][通常論文]
   

  The Raman spectrum of buckyferrocene (Fe(C-60(CH3)(5))C5H5) changes during laser irradiation at 532 nm. A peak at 1465 cm(-1) decreases and a new peak at 1452 cm(-1) emerges, which resembles the change in the 'pentagonal pinch mode' during the photopolymerization of C-60- Photoinduced polymerization is strongly suggested because fragments from the buckyferrocene dimers are observed during the mass spectroscopy of laser desorbed solid samples. The rate constants of the photoinduced change for the powder crystals were determined at various photon intensities, and linearity was observed. The photoinduced change seems to occur extremely fast in densely packed buckyferrocene films fabricated by vacuum deposition. (C) 2004 Elsevier Ltd. All rights reserved.
• Morphological change of C-60 monolayer epitaxial films under photoexcitation

  Y Yamamoto, H Ichikawa, K Ueno, A Koma, K Saiki, T Shimada

  PHYSICAL REVIEW B 70 15 155415  2004年10月 [査読有り][通常論文]
   

  Thin films of C-60 were grown under laser irradiation at various intensities 0-200 mW/mm(2) and their growth shapes were investigated by ex situ atomic force microscopy (AFM) observation. The nucleation density of the first layer decreases with increasing laser intensity, probably due to the temperature rise of the migrating clusters. In addition to this gradual laser intensity dependence, an anomalous enhancement of the nucleation density was observed on irradiation at 50 mW/mm(2), which was attributed to the influence of photopolymerization. As for the second layer, there was a threshold laser intensity (200 mW/mm(2)) at which the nucleation density increased and the shape of the domains became irregular. This is due to the combined effect of hindered migration caused by the polymerized first layer and photopolymerization of the migrating molecules themselves. Energy transfer from the excited substrate to the migrating C-60 molecules is strongly suggested.
• Morphological change of C60 monolayer epitaxial films under photoexcitation

  Y. Yamamoto, H. Ichikawa, K. Ueno, A. Koma, K. Saiki, T. Shimada

  Physical Review B - Condensed Matter and Materials Physics 70 15 1 - 155415 2004年10月 [査読有り][通常論文]
   

  Thin films of C60 were grown under laser irradiation at various intensities 0-200 mW/mm2 and their growth shapes were investigated by ex situ atomic force microscopy (AFM) observation. The nucleation density of the first layer decreases with increasing laser intensity, probably due to the temperature rise of the migrating clusters. In addition to this gradual laser intensity dependence, an anomalous enhancement of the nucleation density was observed on irradiation at 50 mW/mm2, which was attributed to the influence of photopolymerization. As for the second layer, there Was a threshold laser intensity (200 mW/mm2) at which the nucleation density increased and the shape of the domains became irregular. This is due to the combined effect of hindered migration caused by the polymerized first layer and photopolymerization of the migrating molecules themselves. Energy transfer from the excited substrate to the migrating C60 molecules is strongly suggested.
• Controlling molecular motion on the surface by electric field gradient during molecular beam epitaxy of liquid crystal ultrathin films

  T Shimada, M Nagahori, A Koma

  SURFACE SCIENCE 564 1-3 L263 - L269 2004年08月 [査読有り][通常論文]
   

  We studied the effect of a direct electric field with an intensity gradient during the thin film deposition of liquid crystal molecules under ultrahigh vacuum. Alignment of elongated islands was observed when the electric field was higher than the threshold value of 4x10(5) to 5x10(6) Vm(-1), which was dependent on the substrate temperature. Layer-by-layer molecular aggregation in the direction of the higher field was observed when the force due to the field gradient was greater than 10(-20)-10(-19) N. The acceleration of molecular hopping between adjacent sites is not enough to account for the aggregation and enhancement of the long range hopping by the unidirectional force must be involved. The present observation indicates that the motion of a single molecule or a nm-sized cluster on the surface can be controlled by electric fields if the molecule has a permanent dipole. (C) 2004 Elsevier B.V. All rights reserved.
• Molecular orientation and electronic structure of epitaxial bucky ferrocene (Fe(C-60(CH3)(5))C5H5) thin films

  T Kaji, T Shimada, H Inoue, Y Kuninobu, Y Matsuo, E Nakamura, K Saiki

  JOURNAL OF PHYSICAL CHEMISTRY B 108 28 9914 - 9918 2004年07月 [査読有り][通常論文]
   

  Single crystalline epitaxial films of bucky ferrocene (Fe(C-60(CH3)(5))C5H5), a hybrid molecule of C-60 and ferrocene, were grown on MoS2(0001) substrates. By using reflection high-energy electron diffraction (RHEED) amplified by a microchannel plate (MCP), it was found that the lattice constant of the film decreased from 11.3 +/- 0.2 Angstrom at 1-2 monolayer (ML) to 10.2 +/- 0.2 Angstrom at 3 ML or thicker. Both of the lattice constants were incommensurate with that of the substrate, which indicates a new type of epitaxial growth. Valence electronic structures of the films at each thickness were measured with ultraviolet photoelectron spectroscopy (UPS) and the energy levels of molecular orbitals were identified in relation to the molecular orientation in the epitaxial film.
• [Cladribine monotherapy for patients with relapsed or refractory indolent non-Hodgkin lymphoma].

  Nakashima Y, Shimada T, Yamada Y, Choi I, Yufu Y, Uike N

  [Rinsho ketsueki] The Japanese journal of clinical hematology 45 7 568 - 570 7 2004年07月 [査読有り][通常論文]
   

  Cladribine is a purine analogue that is resistant to degradation by adenosine deaminase. We describe the efficacy of cladribine monotherapy in 8 patients with relapsed or refractory indolent non-Hodgkin lymphoma. The median age of the patients was 57 years. All patients were given 1-3 courses of cladribine monotherapy at 0.09 mg/kg/day continuous infusion for 7 days. Although all patients had been treated with rituximab and CHOP-like regimens, the response rate was excellent (85.7%). Thus we consider that cladribine is the first treatment of choice in the patients with relapsed or refractory indolent lymphoma.
• Band structure and molecular orientation of ultrathin epitaxial films of squaric acid

  T Shimada, H Taira, T Miyadera, A Koma, K Saiki

  JOURNAL OF PHYSICAL CHEMISTRY B 108 17 5329 - 5332 2004年04月 [査読有り][通常論文]
   

  Ultraviolet photoelectron spectroscopy of epitaxial films of squaric acid (H2C4O4), a two-dimensional antiferroelectric organic material, is reported. The band structure parallel to the two-dimensional molecular plane was derived, in which the dispersion of the HOMO-2 band was found to be as large as 0.7 eV. The molecular orientation was estimated by analyzing the angular distribution of the photoelectron intensities from various molecular orbitals using independent atomic center approximation.
• Methyl-terminated Si(111) surface as the ultra thin protection layer to fabricate position-controlled alkyl SAMs by using atomic force microscope anodic oxidation

  R Okada, T Miyadera, T Shimada, A Koma, K Ueno, K Saiki

  SURFACE SCIENCE 552 1-3 46 - 52 2004年03月 [査読有り][通常論文]
   

  Methyl-terminated Si(111) (Me-Si(111)) and bilayer-GaSe terminated Si (BGS) surfaces were investigated to explore their usefulness as the protection layer in the fabrication process of nanometer-scale self-assembled monolayers (SAMs). BGS was not stable in the reagent involved in the alkyl SAM formation, whereas Me-Si(111) was suitable for the protection layer. Anodization using atomic force microscope (AFM) and following HF and hexadecene treatments were performed to form nano-scale alkyl SAM lines on the Me-Si(111) surface. It was found from AFM observation and frictional force measurement that only the patterned areas were selectively covered with hexadecyl SAMs. (C) 2004 Elsevier B.V. All rights reserved.
• Accelerated photopolymerization and increased mobility in C-60 field-effect, transistors studied by ultraviolet photoelectron spectroscopy

  T Shimada, T Suetsugu, T Miyadera, Y Yamamoto, A Koma, K Saiki, K Kudo

  APPLIED PHYSICS LETTERS 84 13 2439 - 2441 2004年03月 [査読有り][通常論文]
   

  Ultraviolet photoelectron spectroscopy (UPS) of C-60 thin-film field-effect transistors was measured with biasing gate voltages. A time-dependent change in the electronic structure of the C-60 film was, observed during the UPS measurement, which has never been observed in a C-60 film grown on a conductive substrate. The change was attributed to the accelerated polymerization of C-60 by comparing the UPS with that of the photopolymerized C-60. The polymerization Was associated with the increase in the field-effect electron mobility. This result indicates that mobile carriers produce reactive radicals in organic semiconductors. (C) 2004 American Institute of Physics.
• 有機薄膜FETの電子分光

  島田 敏宏

  電気学会論文誌. C, 電子・情報・システム部門誌 = The transactions of the Institute of Electrical Engineers of Japan. C, A publication of Electronics, Information and System Society 124 6 1229 - 1233 社団法人 電気学会 2004年 [査読無し][通常論文]
   

  Organic thin film FETs have been studied by using electron spectroscopic techniques. Ultraviolet photoelectron spectroscopy has revealed that photo polymerization is enhanced by fabricating FET structure. Energy levels and the effective mass of charge carriers are discussed based on the results of photoelectron spectroscopy and electron energy loss spectroscopy.
• 27pZP-1 有機薄膜トランジスタにおけるキャリヤの空間分布(領域7,領域8合同 : 分子デバイスII)(領域7)

  木口 学, 中山 学, 鳥田 敏宏, 斉木 幸一朗

  日本物理学会講演概要集 59.1.4 837  一般社団法人 日本物理学会 2004年
• 13aPS-13 不純物添加 Bi-2212 単結晶の低温 STM/STS 観察(低温 : 超伝導・金属絶縁体転移, 領域 8)

  福尾 則学, 眞嶋 秀樹, 木野田 剛, 一杉 太郎, 島田 敏宏, 清水 圭輔, 下山 淳一, 岸尾 光二, 長谷川 哲也

  日本物理学会講演概要集 59 0 463 - 463 一般社団法人 日本物理学会 2004年 [査読有り][通常論文]
  
• Accumulation and depletion layer thicknesses in organic field effect transistors

  M Kiguchi, M Nakayama, K Fujiwara, K Ueno, T Shimada, K Saiki

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 42 12A L1408 - L1410 2003年12月 [査読有り][通常論文]
   

  We present a simple but powerful method to determine the thicknesses of the accumulation and depletion layers and the distribution curve of injected carriers in organic field effect transistors. The conductivity of organic semiconductors in thin film transistors was measured in situ and continuously with a bottom contact configuration, as a function of film thickness at various gate voltages. Using this method, the thicknesses of the accumulation and depletion layers of pentacene were determined to be 0.9 nm (V-G = - 15 V) and 5 nm (V-G = 15 V), respectively.
• Photoassisted electrochemical deposition of copper from a bathocuproin complex

  T Shimada, Y Yamamoto, K Saiki, A Koma

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 42 8A L964 - L966 2003年08月 [査読有り][通常論文]
   

  It was found that electrochemical deposition of copper from a [Cu(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline)(2)](+) ([Cu(bcp)(2)](+)) complex can be induced by photoirradiation at a certain cathode potential. It can be used for photopatterning of copper and controlling electrodeposition of copper in microelectronics applications. The mechanism of the photoassisted electrochemical deposition is suggested to be due to the reduced stability of the photoexcited complex.
• Interferometric microscopy observation of the initial stage of electrochemical crystal growth of (DMe-DCNQI)(2)Cu

  T Shimada, T Kaji, K Saiki, A Koma

  JOURNAL OF CRYSTAL GROWTH 253 1-4 351 - 356 2003年06月 [査読有り][通常論文]
   

  Interferometric microscopy was used to observe the initial stage of the crystal growth of an organic charge transfer salt (DMe-DCNQI)(2)Cu by electrochemical reaction. It was found that concentric patterns started to appear after applying the potential difference between the electrodes. Bright rings of the concentric pattern moved outward for about 15 s and slowed down the movement after the period. It shows the change in the solution concentration just after the nucleation. (C) 2003 Elsevier Science B.V. All rights reserved.
• Electron spectroscopy of chemically synthesized ZnS clusters

  Y Kaminuta, A Koma, T Shimada

  SOLID STATE COMMUNICATIONS 125 11-12 581 - 585 2003年03月 [査読有り][通常論文]
   

  Thin films of ionic compounds of ZnS clusters were measured by electron energy loss spectroscopy (EELS) and ultraviolet photoelectron spectroscopy (UPS). A size effect was observed in the valence plasmon energy measured by EELS from which the coherence length of the plasmon excitation can be estimated. The difference between the lowest excitations observed in UPS and EELS can be explained by the final state charging effect of a single cluster ion in UPS, which strongly depends upon the nominal charges of the clusters. (C) 2003 Published by Elsevier Science Ltd.
• Ultraviolet photoelectron spectroscopy of a methyl-terminated Si(111) surface

  T Miyadera, A Koma, T Shimada

  SURFACE SCIENCE 526 1-2 177 - 183 2003年02月 [査読有り][通常論文]
   

  Angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) of a Si(I 11) surface regularly terminated by methyl groups is reported. The electrochemical methylation was performed in inert atmosphere. The cleanliness and I x 1 ordering of the surface were confirmed by Auger electron spectroscopy and reflection high-energy electron diffraction, respectively. The energy band diagram has been obtained from ARUPS and each energy level was assigned from the comparison with the results of hydrogen-terminated Si(I 11) and quantum chemical cluster calculation. (C) 2002 Elsevier Science B.V. All rights reserved.
• Prospects of electron spectroscopy of working organic electronic device structures

  T Shimada, A Koma

  IEICE TRANSACTIONS ON ELECTRONICS E85C 6 1330 - 1331 2002年06月 [査読有り][通常論文]
   

  The prospects of electron spectroscopy of working organic electronic device structures are discussed. The experimental consideration and the result of actual measurement are presented.
• Highly stable passivation of a Si(111) surface using bilayer-GaSe

  K Ueno, H Shirota, T Kawamura, T Shimada, K Saiki, A Koma

  APPLIED SURFACE SCIENCE 190 1-4 485 - 490 2002年05月 [査読有り][通常論文]
   

  As a stable and 'epitaxial' passivation of a Si surface, we propose the bilayer-GaSe termination of a Si(1 1 1) surface. This surface is fabricated by depositing one monolayer of Ga on a clean Si(1 1 1) surface and subsequent annealing in a Se flux at around 520 degreesC, which results in unreconstructed 1 x 1 termination of the Si(1 1 1) surface by bilayer-GaSe. We found by scanning tunneling microscopy observation that slow cooling of the clean Si(1 1 1) surface from 850 to 520 degreesC with simultaneous deposition of a Ga flux results in better termination of the Si(1 1 1) surface. It was also found that this surface is stable against heating around 400 degreesC in O-2 atmosphere of 3 x 10(-3) Pa. By utilizing these properties of the bilayer-GaSe terminated surface, we have succeeded in fabricating ZnO quantum dots on this substrate. (C) 2002 Elsevier Science B.V. All rights reserved.
• Electron spectroscopy of C-60 thin film FET structures

  T Shimada, A Koma

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 41 4B 2724 - 2726 2002年04月 [査読有り][通常論文]
   

  Electron spectroscopy experiments were attempted to the measure the electronic structure of organic field effect transistors (FETs) under a gate bias. Sample structure, experimental condition and results of FETs made of C-60 are described. C-60 FET structures showed irreversible change of the valence spectra during the ultraviolet photoelectron spectroscope measurement under a gate bias voltage. Electron energy loss spectroscopy after the change revealed a substantial lowering of the plasmon energy which indicates that the discrete spherical boundary condition of the molecular plasmon was broken. This suggests polymerization of C-60 by a combined effect of the gate bias and vacuum ultraviolet irradiation.
• 分子エレクトロニクスのためのドライプロセス (特集 分子エレクトロニクスの展望)

  島田 敏宏

  化学工業 52 8 605 - 609 化学工業社 2001年08月 [査読無し][通常論文]
  
• Epitaxial growth and electronic structure of a C-60 derivative prepared by using a solution spray technique

  T Shimada, H Nakatani, K Ueno, A Koma, Y Kuninobu, M Sawamura, E Nakamura

  JOURNAL OF APPLIED PHYSICS 90 1 209 - 212 2001年07月 [査読有り][通常論文]
   

  We demonstrate and analyze the epitaxial film formation of a molecular material that cannot be evaporated in vacuum due to thermal decomposition. A solution of the material is sprayed onto single crystalline van der Waals surfaces using a pulse valve under controlled vapor pressure of the solvent. Monolayer epitaxial films are obtained and we propose that the growth is mediated by liquid ultrathin films formed on the surface. Molecular arrangement and electronic structure of C-60(CH3)(5)H films are studied by reflection high energy electron diffraction and ultraviolet photoelectron spectroscopy, respectively. The present technique will be useful to study the electronic structure of recently synthesized molecular materials. (C) 2001 American Institute of Physics.
• Control of initial growth processes of epitaxial films using pulsed molecular beams

  T Shimada, KA Cho, A Koma

  PHYSICAL REVIEW B 63 15 153404  2001年04月 [査読有り][通常論文]
   

  Kinetics of epitaxial thin film growth was analyzed from the experiments using pulsed organic molecular beams. It was found that a minimum appears in the nucleation density as a function of on-off cycle time when the substrate temperature is near the threshold between growth and reevaporation. This feature can be explained by assuming desorption of molecules induced by mutual collision on the surface, for which orientation-sensitive intermolecular forces are responsible.
• Ordered growth and crystal structure of Alq(3) on alkali halide surfaces

  H Ichikawa, T Shimada, A Koma

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 40 3A L225 - L227 2001年03月 [査読有り][通常論文]
   

  Ordered films of tris-8-hydroxyquionolate-aluminum (Alq(3)) were grown by molecular beam deposition on cleaved KCl and KBr surfaces. The local molecular arrangements in the films were characterized by two-dimensional analysis of multiazimuth reflection medium energy electron diffraction (RMEED). A new type of curved one-dimensional crystallographic ordering was observed on KBr while a continuous point-on-line-type ordering was observed on KCl. Growth of the crystals consisting of mer isomers is suggested from the observed triple period superstructure.
• Control of initial growth processes of epitaxial films using pulsed molecular beams

  T. Shimada, K. A. Cho, A. Koma

  Physical Review B - Condensed Matter and Materials Physics 63 15 2001年 [査読有り][通常論文]
   

  Kinetics of epitaxial thin film growth was analyzed from the experiments using pulsed organic molecular beams. It was found that a minimum appears in the nucleation density as a function of on-off cycle time when the substrate temperature is near the threshold between growth and reevaporation. This feature can be explained by assuming desorption of molecules induced by mutual collision on the surface, for which orientation-sensitive intermolecular forces are responsible. © 2001 The American Physical Society.
• Surface migration dynamics of a planar organic molecule studied by pulsed molecular beam scattering

  T. Shimada, R. Hashimoto, J. Koide, Y. Kamimuta, A. Koma

  Surface Science 470 1-2 L52 - L56 2000年12月20日 [査読有り][通常論文]
   

  Pulsed molecular beam scattering technique was applied to analyze the dynamics of a large planar molecule migrating on various surfaces (Au(1 1 1), graphite(0 0 0 1), mica (0 0 1), amorphous silicon oxide). It was found that molecules can stay on the surface for seconds without condensation. Activation energies have a magnitude comparable to those of a single ionic or covalent bonding, which reflects the additivity of the van der Waals interaction. Possible contribution of the diffusion to the surface residence time is discussed.
• OME2000-42 パルス分子線を用いた有機エピタキシー素過程の探求

  島田 敏宏

  電子情報通信学会技術研究報告. OME, 有機エレクトロニクス 100 245 1 - 4 一般社団法人電子情報通信学会 2000年07月21日 [査読無し][通常論文]
   

  パルス分子線を用いて有機分子の真空蒸着における膜形成素過程の研究を行っている。水素フタロシアニンを様々な基板表面に照射し、反射時間プロファイルを測定した結果、低い基板温度においては秒単位の滞在時間を持つことがわかった。アレニウスプロットは直線にのり、表面・分子相互作用を決める特徴的なエネルギーが求められた。また、パルス分子線により成長したキナクリドン薄膜を原子間力顕微鏡で観察した結果、パルス幅に対して核形成密度に極小があらわれることが分かった。理論的解析を行い、分子2個が衝突することによる脱離過程がこの原因であることを明らかにした。
• Nucleation control in organic selective epitaxy by pulsed molecular beam technique

  KA Cho, T Shimada, A Koma

  PHYSICA E 7 3-4 887 - 890 2000年05月 [査読有り][通常論文]
   

  Enhancement of the selectivity in organic molecular beam epitaxy was achieved by using pulsed molecular beams. It utilizes the nucleation kinetics before reaching stationary state of the growth. The time scale needed for the stationary state is estimated by changing the cycle time of the pulses. (C) 2000 Elsevier Science B.V. All rights reserved.
• Velocity distribution of organic molecules emitted from effusion cells measured by time-of-flight technique

  T Shimada, J Koide, KA Cho, A Koma

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 17 2 615 - 618 1999年03月 [査読有り][通常論文]
   

  Velocity distribution of the molecules emitted from effusion cells commonly used in molecular beam epitaxy was measured by using time-of-flight technique. The result for organic molecular phthalocyanine can be fitted by a shifted Maxwellian distribution. The effects of the temperature and the aspect ratios of the sources are discussed. (C) 1999 American Vacuum Society. [S0734-2101(99)03502-2].
• Monolayer films of liquid crystal 12CB grown by molecular beam deposition on cleaved surfaces of alkali halides

  T Shimada, H Nagahori, A Koma

  SURFACE SCIENCE 423 2-3 L285 - L290 1999年03月 [査読有り][通常論文]
   

  Ultrathin films of liquid crystal 12CB with monolayer-order thickness were grown on cleaved (001) surfaces of NaCl, KC1 and KBr substrates by molecular beam deposition. The molecular arrangement and the morphology of the films were analyzed by high sensitivity reflection high energy electron diffraction and atomic force microscopy (AFM), respectively. Epitaxial films were formed on KCI and KBr, whereas only one-dimensional ordering was observed on NaCl. AFM images of 12CB monolayers grown on NaCl just below the bulk transition temperature showed a characteristic morphology resembling an arabesque in sub-micron scales. It is attributed to orientational fluctuation of local crystal axes at growth fronts. (C) 1999 Elsevier Science B.V. All rights reserved.
• Selective epitaxial growth of organic molecules on patterned alkali halide substrates

  T Shimada, T Sakurada, A Koma

  APPLIED PHYSICS LETTERS 74 7 941 - 943 1999年02月 [査読有り][通常論文]
   

  Selective epitaxial growth of organic materials is found and analyzed. It is observed during the molecular beam epitaxy of organic molecules and charge transfer complexes on ionic surfaces. The selectivity comes from lattice matching condition on critical nuclei formation in contrast to compound semiconductors for which covalent chemical bonding plays essential roles. It can be utilized to fabricate micropatterns of crystalline organic materials accompanied by lithography processes of alkali halides using NH3 plasma. Feasibility of building three-dimensional microstructures has also been shown, which is readily applicable to make photonic crystals from optically functional organic materials. (C) 1999 American Institute of Physics. [S0003-6951(99)02507-3].
• Effect of growth temperature and substrate materials on epitaxial growth of coronene

  KA Cho, T Shimada, M Sakurai, A Koma

  JOURNAL OF APPLIED PHYSICS 84 1 268 - 274 1998年07月 [査読有り][通常論文]
   

  Epitaxial growth of coronene (C24H12) was studied on substrates having no dangling bonds, such as hydrogen-terminated Si(lll), MoS2, MoTe2, and muscovite by using reflection high-energy electron diffraction. It was found that the sticking coefficient and the maximum thickness of the epitaxial films are strongly dependent on the substrate materials as well as on the growth temperature. The effectiveness of molecular mechanics calculation was examined by comparing the calculated stabilization energies with the experimental results. Importance of the electronic structure of substrates has been revealed and its effect was estimated quantitatively using the Lifshitz theory. The tendency that the interfacial dispersion force is stronger for smaller band gap materials has been shown from theoretical consideration. (C) 1998 American Institute of Physics.
• Epitaxial growth of squaric acid

  T Shimada, H Taira, A Koma

  CHEMICAL PHYSICS LETTERS 291 3-4 419 - 424 1998年07月 [査読有り][通常論文]
   

  Ultrathin film growth of squaric add (H2C4O4) has been attempted on (001) surfaces of various alkali halides. Epitaxial films were obtained on KCl, NaBr and KBr substrates. Ultraviolet optical absorption spectra of the films were strongly dependent on the substrates, suggesting a possibility of modifying correlated hydrogen bonding by 'epitaxial pressure'. (C) 1998 Elsevier Science B.V. All rights reserved.
• Preparation and magnetic properties of manganese(II) phthalocyanine thin films

  H Yamada, T Shimada, A Koma

  JOURNAL OF CHEMICAL PHYSICS 108 24 10256 - 10261 1998年06月 [査読有り][通常論文]
   

  We report the molecular beam epitaxy (MBE) growth of the manganese(II) phthalocyanine thin films with unique crystal structure and the measurement of their magnetic properties. The epitaxial films were grown on hydrogen-terminated Si(111) substrates. Reflection high energy electron diffraction observations showed that the crystal structure of the films is different from that of the bulk crystal. A large magnetic anisotropy was observed in the measurements with the SQUID magnetometer. The films did not show canted ferromagnetism which is usually observed in the beta-type crystal of manganese phthalocyanine. The magnetic susceptibility measured with magnetic field normal to the substrate obeyed the Curie-Weiss law with a negative Curie-Weiss constant, indicating the existence of the antiferromagnetic interaction. The negative Curie-Weiss constant was also observed in disordered films of manganese phthalocyanine. The variation of magnetic properties between the bulk crystal and the films is explained in terms of the difference in superexchange interaction caused by microscopic modification of the crystal structure, i.e., the stacking arrangement of the molecules. (C) 1998 American Institute of Physics.
• Electronic structures at the interfaces between copper phthalocyanine and layered materials

  T Shimada, K Hamaguchi, A Koma, FS Ohuchi

  APPLIED PHYSICS LETTERS 72 15 1869 - 1871 1998年04月 [査読有り][通常論文]
   

  Copper phtalocyanine (CuPc) films with the thickness controlled in molecular scales have been grown epitaxially on (0001) surfaces of layered materials, and electronic interaction at the interfaces have been studied by photoelectron spectroscopy. Materials with different electronic properties having different work functions (E-vac) were chosen as the substrates; semiconducting MoTe2 (E-vac=4.0 eV), semi-metallic highly oriented pyrolytic graphite (E-vac=4.5 eV) and metallic TaSe2 (E-vac=5.5 eV). Formation of interface dipole layers was found at CuPc/TaSe2 interfaces and molecular orbitals involved were identified. (C) 1998 American Institute of Physics.
• Electron energy-loss spectroscopy of (DMe-DCNQI)(2)Cu

  M Mochida, T Shimada, A Koma

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 15 4 2119 - 2121 1997年07月 [査読有り][通常論文]
   

  Electron energy-loss spectroscopy (EELS) has been applied to in situ prepared (DMe-DCNQI)(2)Cu (DMe-DCNQI=2,5-dimethyl-N,N'-dicyanoquinonediimine). The intensity of the loss peaks changed significantly with the primary electron energies. It is probably due to the matrix element effects of the EELS. In conjunction with photoelectron spectroscopy using synchrotron radiation, the nature of the unoccupied levels has been elucidated. (C) 1997 American Vacuum Society.
• Thermal desorption measurement of ultrathin epitaxial organic films by optical spectroscopy

  T Shimada, H Taira, A Koma

  SURFACE SCIENCE 384 1-3 302 - 307 1997年07月 [査読有り][通常論文]
   

  Thermal desorption of epitaxial films of vanadyl phthalocyanine (VOPc:C32N8H16VO) and squaric acid (SQ:C4O4H2) was measured by using temperature programmed optical absorption spectroscopy. The activation energies for the desorption and pre exponential factors were determined by measuring the amount of the molecules remaining in the film. Change in the molecular arrangement of VOPc during the desorption was detected from the spectra. The effects of hydrogen bonding and antiferroelectric transition of SQ are discussed. (C) 1997 Elsevier Science B.V.
• Characterizing reactions to fabricate thin films of charge transfer complexes by synchrotron photoelectron spectroscopy: A case study of DCNQI-Cu

  T Shimada, M Mochida, A Koma

  APPLIED SURFACE SCIENCE 113 322 - 325 1997年04月 [査読有り][通常論文]
   

  Ultraviolet photoelectron spectroscopy with various photon energies using synchrotron radiation was used to characterize chemical reactions associated with thin film growth of organic charge transfer complex (DMe-DCNQI)(2)Cu. Other molecular systems H2Pc, CuPc and C-60 were also studied to clarify the origin of the systematic relation between the spectra and the incident photon energy. Characteristic photon energy dependence of the photo-ionization cross section of molecular orbitals is useful to analyze the intermolecular reactions.
• Epitaxial growth of organic molecules on vicinal surfaces of single crystals

  T Shimada, T Sakurada, A Koma

  ELECTROCHEMICAL SYNTHESIS AND MODIFICATION OF MATERIALS 451 167 - 172 1997年 [査読有り][通常論文]
   

  Ultrathin film growth of vanadyl phthalocyanine was attempted on vicinal surfaces of hydrogen-terminated Si(111) in order to see the effect of regularly spaced steps to the growth feature. It has been observed that molecular arrangement was substantially affected when the terrace width was narrower than 2 similar to 4 times of the molecular lattice constants. This result is probably due to the weakness of molecular interaction in the material and it accounts for the reason why ordinary graphoepitaxy has not been successful for the organic thin films.
• Polytypes and crystallinity of ultrathin epitaxial films of layered materials studied with grazing incidence X-ray diffraction

  T Shimada, H Nishikawa, A Koma, Y Furukawa, E Arakawa, K Takeshita, T Matsushita

  SURFACE SCIENCE 369 1-3 379 - 384 1996年12月 [査読有り][通常論文]
   

  The structure of ultrathin epitaxial films of layered NbSe2 and TaSe2 grown on Se-terminated GaAs((111) over bar) substrates was determined by grazing incidence X-ray diffraction. It was found that the crystallographic polytypes of the films were dependent on the growth temperatures. The temperature range for the growth of octahedrally coordinated TaSe2 was different from that of the bulk. Disappearance of 3R-type portion in NbSe2 at a high growth temperature will be favorable to fabricate superconducting ultrathin epitaxial films.
• Epitaxial growth of TiSe2 thin films on Se-terminated GaAs(111)B

  H Nishikawa, T Shimada, A Koma

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 14 5 2893 - 2896 1996年09月 [査読有り][通常論文]
   

  Epitaxial growth of TiSe2 films on Se-terminated GaAs(111)B substrates were carried out at different growth temperature by molecular beam epitaxy. Grown films have been investigated by reflection high energy electron diffraction, Auger electron spectroscopy, and measurements of resistivity parallel to the surface. TiSe2 epitaxial films have been obtained at various temperatures, but the optimum growth temperature was determined to be 400 degrees C. A charge density wave transition has been observed in the resistivity of the film grown at 400 degrees C, indicating that it has a good quality comparable to a bulk single crystal. (C) 1996 American Vacuum Society.
• Epitaxial growth of metal phthalocyanines on hydrogen terminated vicinal surfaces of Si(111)

  T Shimada, A Suzuki, T Sakurada, A Koma

  APPLIED PHYSICS LETTERS 68 18 2502 - 2504 1996年04月 [査読有り][通常論文]
   

  Hydrogen-terminated vicinal Si(lll) surfaces provide quasi-van der Waals substrates with regularly spaced atomic height steps for the epitaxy of organic material films. Molecular beam epitaxy of vanadyl and copper phthalocyanines (VOPc and CuPc) was attempted on just-cut and 7 degrees-miscut surfaces in order to investigate the effect of the steps on the epitaxial growth feature. The molecular arrangement of the films was characterized by a new technique using multiple-azimuth reflection high energy electron diffraction. Growth on misoriented substrates producted VOPc monolayer films consisting of one-dimensional chains nearly aligned to the steps and multilayer CuPc films with controlled domain orientations. (C) 1996 American Institute of Physics.
• Patterning of epitaxial organic films by selective epitaxial growth

  A Suzuki, T Shimada, A Koma

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 35 2B L254 - L257 1996年02月 [査読有り][通常論文]
   

  A new method of patterning crystalline organic molecular films is proposed and demonstrated. It utilizes a selective growth, or the difference in the sticking coefficient of an organic material on various inorganic substrates in a certain temperature range. The object structure is first patterned on a single-crystalline substrate with an epitaxial film of a different material grown by molecular beam epitaxy (MBE) through a mask, and then a beam of the organic molecule is irradiated uniformly after removing the mask.
• WORK FUNCTION AND PHOTOTHRESHOLD OF LAYERED METAL DICHALCOGENIDES

  T SHIMADA, FS OHUCHI, BA PARKINSON

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 33 5A 2696 - 2698 1994年05月 [査読有り][通常論文]
   

  Work functions and photothreshold values of various layered metal dichalcogenides (ZrSe2, HfSe2, NbSe2, 1T-TaS2, 2H-TaS2, MoS2, MoSe2, alpha-MoTe2, SnS2, SnSe2) have been measured by a photoemission technique. The measured photothreshold values, except for Sn compounds, are compared with the calculated values based on various band models. The agreement between the observed and calculated values is satisfactory for most of the materials.
• STRUCTURE DETERMINATION OF ULTRATHIN NBSE2 FILMS BY GRAZING-INCIDENCE X-RAY-DIFFRACTION

  T SHIMADA, Y FURUKAWA, E ARAKAWA, K TAKESHITA, T MATSUSHITA, H YAMAMOTO, A KOMA

  SOLID STATE COMMUNICATIONS 89 7 583 - 586 1994年02月 [査読有り][通常論文]
   

  Grazing incidence x-ray diffraction (GID) technique was applied to determine the three dimensional structures of NbSe2 films grown by van der Waals epitaxy. Atomic arrangements along the surface normal in nm-order films were established from the analysis of Bragg rod profiles measured with GID. The obtained structural polytypes of the films grown on HOPG and Se terminated GaAs(111BAR) were 2Hb and a mixture of 2Hb and 3R, respectively. This result indicates that the polytypes are controlled by the substrate materials in van der Waals epitaxy.
• POLYTYPES AND CHARGE-DENSITY WAVES OF ULTRATHIN TAS2 FILMS GROWN BY VAN-DER-WAALS EPITAXY

  T SHIMADA, FS OHUCHI, A KOMA

  SURFACE SCIENCE 291 1-2 57 - 66 1993年07月 [査読有り][通常論文]
   

  Ultrathin films of TaS2, a two-dimensional metal known for charge density waves (CDWs) and polytypes, have been grown epitaxially on various layered substrates by molecular beam epitaxy and characterized with surface science techniques. STM image of the films shows irregular modulation which has similarity with that of the CDW. Ta(4f) XPS spectra of monolayer films have a correlation with the work functions of the substrates, probably due to the modification of the polytypes and the CDWs. The importance of the formation energy of the electric dipole layer at the interface is discussed.
• Polytypes and charge density waves of ultrathin TaS2 films grown by van der Waals epitaxy

  Toshihiro Shimada, FumioS. Ohuchi, Atsushi Koma

  Surface Science Letters 291 1-2 1993年07月
• MOLECULAR-BEAM EPITAXY OF SNSE2 - CHEMISTRY AND ELECTRONIC-PROPERTIES OF INTERFACES

  T SHIMADA, FS OHUCHI, A KOMA

  JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS 32 3A 1182 - 1185 1993年03月 [査読有り][通常論文]
   

  A layered material SnSe2 was grown epitaxially on various layered materials (MoS2, NbSe2, graphite), while reacting with Al2O3(0001) substrates. The films were characterized by means of X-ray photoemission spectroscopy, reflection high energy electron diffraction, and scanning tunneling microscopy. The observed band bending was consistent to the work function difference between the film and the substrate, indicating the Schottky limit property of the junctions. Applications of this system are discussed.
• THERMAL-DECOMPOSITION OF SNS2 AND SNSE2 - NOVEL MOLECULAR-BEAM EPITAXY SOURCES FOR SULFUR AND SELENIUM

  T SHIMADA, FS OHUCHI, BA PARKINSON

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 10 3 539 - 542 1992年05月 [査読有り][通常論文]
   

  New sources of selenium and sulfur for UHV preparation of thin films are described. These sources, utilizing the high temperature thermal decomposition of SnSe2 and SnS2, are bakeable to at least 300-degrees-C providing much more convenience than element Se and S sources. The thermal decomposition is studied with thermal gravitometry, mass spectrometry, and x-ray photoemission spectroscopy. The utility of the sources is demonstrated by the epitaxial growth of TiSe2 on MoS2.
• Heteroepitaxial growth of alkali halide thin films on GaAs substrates

  Koichiro Saiki, Yuji Nakamura, Atsushi Koma

  Surface Science 269-270 C 790 - 796 1992年05月 

  The growth of alkali halide has been examined on GaAs(111)A, (111)B and (001) substrates. NaCl with a misfit of 0.4% with respect to GaAs grows epitaxially on those GaAs substrates for substrate temperatures between 150°C and 250°C. In the case of growth on (001), the crystallographic axes align with those of the substrate and the grown film always has a flat surface. In the case of growth on (111), the crystallographic orientation of the grown NaCl differs by 180° between the (111)A and (111)B faces and the surface of the grown films consists of triangular pyramids with three {001} faces. From those results, a simple model for NaCl/GaAs(111) heterostructures is proposed. © 1992.
• 25p-ZG-11 還移金属ダイカルコゲナイドの角度依存磁気抵抗効果

  島田 敏宏, 吉井 賢資, 斉木 幸一朗, 小間 篤

  秋の分科会予稿集 1992.2 119  一般社団法人 日本物理学会 1992年
• EPITAXIAL-GROWTH AND CHARGE-DENSITY WAVE OF TASE2

  T SHIMADA, FS OHUCHI, BA PARKINSON

  PHASE TRANSFORMATION KINETICS IN THIN FILMS 230 231 - 236 1992年 [査読有り][通常論文]
  
• GROWTH OF MOSE2 THIN-FILMS WITH VANDERWAALS EPITAXY

  FS OHUCHI, T SHIMADA, BA PARKINSON, K UENO, A KOMA

  JOURNAL OF CRYSTAL GROWTH 111 1-4 1033 - 1037 1991年05月 [査読有り][通常論文]
   

  The concept of Van der Waals epitaxy that has been recently introduced removes severe lattice matching requirement by using materials which only have strong bonding in two dimensions. We demonstrate that an epilayer of MoSe2 deposited on various substrates can produce films of high crystalline quality despite of large mismatch. RHEED oscillation, observed in-situ for growing MoSe2 epilayers, shows a layer-by-layer growth with evidence for for bilayer type growth, from which the 2H(b) polytype is determined. STM provides real space images of the morphology of the epilayer, and shows novel structures resulting from the large lattice mismatch where the epilayer atoms are commensurated.
• RHEED OSCILLATION DURING THE EPITAXIAL-GROWTH OF LAYERED MATERIALS

  T SHIMADA, FS OHUCHI, A KOMA

  ADVANCES IN SURFACE AND THIN FILM DIFFRACTION 208 47 - 52 1991年 [査読有り][通常論文]
  
• EPITAXIAL-GROWTH OF TRANSITION-METAL DICHALCOGENIDES ON CLEAVED FACES OF MICA

  K UENO, K SAIKI, T SHIMADA, A KOMA

  JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A-VACUUM SURFACES AND FILMS 8 1 68 - 72 1990年01月 [査読有り][通常論文]
  
• HETEROEPITAXIAL GROWTH OF LAYERED TRANSITION-METAL DICHALCOGENIDES ON SULFUR-TERMINATED GAAS (111) SURFACES

  K UENO, T SHIMADA, K SAIKI, A KOMA

  APPLIED PHYSICS LETTERS 56 4 327 - 329 1990年01月 [査読有り][通常論文]
  
• RHEED intensity Oscillation during Epitaxial Growth of Layered Materials

  Toshihiro Shimada, Hideki Yamamoto, Koichiro Saiki, Atsushi Koma

  Japanese Journal of Applied Physics 29 11 L2096 - L2098 1990年 [査読有り][通常論文]
   

  Diffracted beam intensities in reflection high energy electron diffraction (RHEED) have been observed to oscillate during the epitaxial growth of NbSe2and MoSe2on GaAs(111) infstrates. This is the first observation of RHEED oscillation in layered materials, to the author's knowledge. Monolayer- and bilayer-mode oscillations have been observed at different diffraction points. The existence of the bilayer-mode oscillation leads to the determination of the polytype of the grown films. it has also been shown that the antiphase portion of the grown film is considerably small. © 1990 IOP Publishing Ltd.
• APPLICATION OF VANDERWAALS EPITAXY TO HIGHLY HETEROGENEOUS SYSTEMS

  K SAIKI, K UENO, T SHIMADA, A KOMA

  JOURNAL OF CRYSTAL GROWTH 95 1-4 603 - 606 1989年02月 [査読有り][通常論文]
  
• The Transisopropylation of Naphthalene

  Keizo Shimada, Shizuo Nagahama

  Bulletin of the Chemical Society of Japan 48 3 1059 - 1060 1975年03月
• \textlessWO2010117012A1 - Permeability evaluation device and evaluation method .pdf\textgreater

  敏宏 島田
• \textlessWO2010117012A1 - Permeability evaluation device and evaluation method .pdf\textgreater

  敏宏 島田
• \textlessWO2010117012A1 - Permeability evaluation device and evaluation method .pdf\textgreater

  敏宏 島田
• \textless表面科学30_7.pdf\textgreater

  敏宏 島田
• \textless表面科学30_7.pdf\textgreater

  敏宏 島田
• \textlessWO2010117012A1 - Permeability evaluation device and evaluation method .pdf\textgreater

  敏宏 島田

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  後藤真菜美, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 66th 2019年
• D0₁₉型X₃Sn(X=Fe,Mn)薄膜の作製とその磁気伝導特性

  前野央, 柳瀬隆, 島田敏宏, 辻川雅人, 辻川雅人, 白井正文, 白井正文, 長浜太郎 応用物理学会春季学術講演会講演予稿集(CD-ROM) 66th 2019年
• Li₂C₂を原料とする新規ナノカーボンの合成

  小谷直人, 田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 66th 2019年
• アセン類への高温高圧処理による炭素固体の合成

  山根伊知郎, 柳瀬隆, 長浜太郎, 島田敏宏 高圧討論会講演要旨集 60th 2019年
• 磁性体ナノワイヤのCVD合成と単一ナノワイヤに対する物性評価

  淡嶋義弘, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• 乱流を用いたCVD法によるMoO₂ナノワイヤの成長メカニズムおよびその硫化によるMoS₂の合成

  後藤真菜美, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• アルカリ金属加熱処理によるダイヤモンドNV中心の蛍光の変化

  竹鼻大貴, 田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• ポリアセン類を前駆体とした高圧処理による新規炭素固体の合成

  山根伊知郎, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 80th 2019年
• Fe₃O₄(001)/MgO(001)/Fe(001)強磁性トンネル接合における負のトンネル磁気抵抗効果

  安井彰馬, 岡林潤, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 43rd 2019年
• CoFe₂O₄/Pt界面における磁気近接効果の電圧制御

  野土翔登, 山本匠, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 43rd 2019年
• スピネル型フェライト薄膜を含むスピントロニクスデバイスの開発

  長浜太郎, 高橋望, 安井彰馬, 島田敏宏 日本表面真空学会東北・北海道支部学術講演会講演予稿集 2018 2019年
• 窒化ホウ素ナノチューブCVD合成のナノ粒子触媒の探索

  島田敏宏, 白鳥達也, 山本靖典, 柳瀬隆, 長浜太郎 セラミックス基礎科学討論会講演要旨集 57th 2019年
• CVD法によるMoS₂ナノチューブの合成

  島田敏宏, 後藤真菜美, 張美斉, 柳瀬隆, 長浜太郎 日本表面真空学会東北・北海道支部学術講演会講演予稿集 2018 2019年
• Fe₃O₄(110)/非磁性金属/Feの磁化過程および非磁性層依存性

  大森圭太, 川井智博, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 53rd-14th 2018年
• CoFe₂O₄/Pt/CoFe₂O₄三層膜におけるスピンホール磁気抵抗効果

  山本匠, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 53rd-14th 2018年
• 新規Fe_1-xSn_x合金薄膜の結晶構造と磁気特性

  後藤有貴, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 53rd-14th 2018年
• Fe₃O₄(100)電極とMgAlO_x(100)バリアを用いた磁気トンネル接合の作製と評価

  山本雄太, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 53rd-14th 2018年
• 化学気相成長法によるFeナノワイヤの作製と磁気抵抗効果

  柳瀬隆, 荻原初夏, 長浜太郎, 長島一樹, 柳田剛, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 65th 2018年
• Fe/AlO_x/Fe₃O₄磁気トンネル接合における逆磁気キャパシタンス効果

  海住英生, 長浜太郎, 佐々木駿, 島田敏宏, 北上修, 三澤貴浩, 藤岡正弥, 西井準治, XIAO Gang 日本物理学会講演概要集(CD-ROM) 73 (1) 2018年
• Pt/CoFe₂O₄二層膜における磁気近接効果とその膜厚・温度依存性

  野土翔登, 山本匠, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会春季学術講演会講演予稿集(CD-ROM) 65th 2018年
• MoS₂単層膜の成長条件・処理方法による蛍光スペクトルの変化

  島田敏宏, 上原史也, 柳瀬隆, 長浜太郎 日本表面科学会東北・北海道支部講演会講演予稿集 2017 2018年
• 金属酸化物ナノ粒子を触媒としたMoS₂ナノチューブCVD成長

  WENG Mengting, ZHANG Meiqi, 柳瀬隆, 上原史也, 長浜太郎, 島田敏宏 日本セラミックス協会年会講演予稿集(CD-ROM) 2018 2018年
• 窒素含有アセンの合成とフラックス蒸発法による単結晶成長

  酒井宣彦, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年
• CoFe₂O₄/Pt/CoFe₂O₄三層膜のスピンホール磁気抵抗効果

  山本匠, 野土翔登, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 42nd 2018年
• 磁気近接効果を用いたPt/CoFe₂O₄超薄膜の磁気特性評価

  野土翔登, 山本匠, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 42nd 2018年
• フラックス蒸発法による有機半導体単結晶成長と応用

  島田敏宏, 酒井宣彦, LI Mingzhe, YANG Xiaoran, 長浜太郎, 柳瀬隆 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年
• プラズマCVDによる窒化ホウ素合成における原料と触媒の影響

  白鳥達也, 高見拓哉, 三浦拓也, 柳瀬隆, 長浜太郎, 山本靖典, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年
• 分子結晶への超高圧印加による新規窒素含有炭素材料の探索

  山根伊知郎, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 79th 2018年
• 窒素含有アセン結晶への高圧印加による新規窒素含有炭素材料の探索

  山根伊知郎, 柳瀬隆, 長浜太郎, 島田敏宏 高圧討論会講演要旨集 59th 2018年
• Mn-Fe酸化物ナノ粒子のカーボンナノチューブ成長触媒活性

  柳瀬隆, 白鳥達也, 三浦拓也, WENG Mengting, 長浜太郎, 島田敏宏 セラミックス基礎科学討論会講演要旨集 56th 2018年
• 有機分子結晶の高圧処理による新規窒素含有炭素材料の合成

  山根伊知郎, 柳瀬隆, 長浜太郎, 島田敏宏 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 31st 2018年
• MoS₂のCVD成長-触媒ナノ粒子を用いたナノチューブ成長と薄膜の不純物・欠陥の解析

  島田敏宏, 上原史也, 後藤真菜美, 田村貴大, 柳瀬隆, 長浜太郎 日本表面真空学会学術講演会講演要旨集 2018 2018年
• グラッシーカーボン薄膜の作製と光・電気特性の評価

  上部宏晃, 長谷川幸樹, 柳瀬隆, 長浜太郎, 島田敏宏 セラミックス基礎科学討論会講演要旨集 55th 2017年
• 立方晶窒化ホウ素の表面科学と薄膜成長

  高見拓哉, 田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 セラミックス基礎科学討論会講演要旨集 55th 2017年
• 化学気相成長法によるFeナノワイヤの作製と特性評価

  荻原初夏, 柳瀬隆, 長浜太郎, 島田敏宏 セラミックス基礎科学討論会講演要旨集 55th 2017年
• MoS₂ナノチューブ成長における触媒粒子サイズ効果

  MENGTING Weng, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 64th 2017年
• MgO(100)基板上のエピタキシャルSn_xFe_3-xO₄薄膜

  荒木真人, 梶田博樹, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会春季学術講演会講演予稿集(CD-ROM) 64th 2017年
• 立方晶窒化ホウ素高指数面の作製とダイヤモンドヘテロ成長

  田村貴大, 高見拓哉, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 64th 2017年
• 化学気相成長法によるFeナノワイヤの作製と評価

  荻原初夏, 柳瀬隆, 長浜太郎, 島田敏宏 日本セラミックス協会年会講演予稿集(CD-ROM) 2017 2017年
• 立方晶窒化ホウ素高指数面の作製とダイヤモンドヘテロ成長

  高見拓哉, 田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 日本セラミックス協会年会講演予稿集(CD-ROM) 2017 2017年
• 化学気相蒸着法によるMo_xNb_1-xS₂薄膜の作製

  渡邉翔, 上原史也, 柳瀬隆, 長浜太郎, 島田敏宏 日本セラミックス協会年会講演予稿集(CD-ROM) 2017 2017年
• 遷移金属ダイカルコゲナイドのCVD精密制御

  島田敏宏, 渡邉翔, 上原史也, WENG Mengting, 柳瀬隆, 長浜太郎 日本表面科学会東北・北海道支部講演会講演予稿集 2016 2017年
• 立方晶窒化ホウ素の高指数表面の作製と性質

  島田敏宏, 田村貴大, 高見拓哉, 柳瀬隆, 長浜太郎 日本表面科学会東北・北海道支部講演会講演予稿集 2016 2017年
• Fe/AlO_x/Fe₃O₄における逆トンネル磁気キャパシタンス効果

  海住英生, 長浜太郎, 佐々木駿, 島田敏宏, 北上修, 三澤貴浩, 藤岡正弥, 西井準治, XIAO Gang 日本磁気学会学術講演概要集 41st 2017年
• 立方晶窒化ホウ素の任意指数面単結晶基板の作製と表面反応の観察

  田村貴大, 高見拓哉, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 78th 2017年
• CoFe₂O₄/Pt/CoFe₂O₄サンドイッチ膜におけるスピンホール磁気抵抗効果

  山本匠, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 78th 2017年
• CVD法によるMoS₂単層膜の作製と硫黄アニールによる効果

  上原史也, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 78th 2017年
• MgO(100)基板上のエピタキシャルSn_xFe_3-xO₄薄膜の作製

  荒木真人, 梶田博樹, 柳瀬隆, 島田敏宏, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 52nd-13th 2017年
• γ-Al₂O₃バッファー層を用いたSi基板上のFe₃O₄作製

  高橋望, HUMINIUC Teoder, 山本雄太, 柳瀬隆, 島田敏宏, 廣畑貴文, 長浜太郎 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 52nd-13th 2017年
• 有機デバイスにおける水蒸気バリア性の高精度・高速測定と標準化技術 (特集 有機ELの長寿命化,欠陥対策に欠かせない ハイバリアフィルムおよび封止材料のバリア性向上)

  島田 敏宏, 柳瀬 隆, 吉田 肇, 楯 和也, 今村 貴浩, 細岡 也寸志 Material stage 16 (8) 56 -60 2016年11月
• ナノ粒子を触媒とした鉄ナノワイヤの作製

  柳瀬隆, 荻原初夏, 三浦拓也, WENG Mengting, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 63rd 2016年
• 固体挿入プラズマCVD法によるBiを含む新規炭素系物質の合成

  田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 63rd 2016年
• 有機半導体に対する変形効果の計算機シミュレーション

  島田敏宏, 山川貴恵, 柳瀬隆, 長浜太郎 応用物理学会春季学術講演会講演予稿集(CD-ROM) 63rd 2016年
• Fe₃O₄(110)を用いた強磁性トンネル接合の磁気伝導特性

  佐々木駿, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 63rd 2016年
• 大気圧CVDによるFeナノワイヤの合成

  島田敏宏, 荻原初夏, 翁夢てい, 長浜太郎, 柳瀬隆 日本表面科学会東北・北海道支部講演会講演予稿集 2015 2016年
• Fe₃O₄電極とMgOバリアを用いたトンネル磁気抵抗素子の作製

  山本雄太, 佐々木駿, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 40th 2016年
• Fe₃O₄(110)/非磁性金属/Fe系多層膜における飽和磁場の非磁性金属層膜厚に対する依存性

  大森圭太, 川井智博, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 40th 2016年
• 固体挿入法により合成されたEu-B多結晶ダイヤモンドの電気特性の評価

  高見拓哉, 田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年
• 化学気相蒸着法によるMo_xNb_1-xS₂薄膜の作製

  渡邉翔, 上原史也, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年
• 化学気相成長法によるFeナノワイヤの作製と特性評価

  荻原初夏, 柳瀬隆, 長浜太郎, 長島一樹, 柳田剛, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年
• 新規グラッシーカーボン薄膜の作製と光学特性および電気特性の評価

  上部宏晃, 長谷川幸樹, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 77th 2016年
• 三次元ネットワーク高分子を用いた立方晶窒化ホウ素結晶上への新規炭素薄膜の合成

  島田敏宏, 長谷川幸樹, 柳瀬隆, 長浜太郎, 山口誠 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 29th 2016年
• 中・遠赤外メタマテリアルを目指す耐火物薄膜の微細加工技術の開発

  島田敏宏, 高見拓哉, 田村貴大, 柳瀬隆, 長浜太郎 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 29th 2016年
• Fe₃O₄(110)を用いた磁気トンネル接合の伝導特性評価

  佐々木駿, 長浜太郎, 島田敏宏 応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集 51st-12th 2016年
• 層状金属カルコゲナイドCVD成長におけるナノ形態制御

  島田敏宏, 柳瀬隆, 渡邉翔, WENG Mengting 表面科学学術講演会講演要旨集 35th (0) 1 -2 2015年12月01日 [査読無し][通常論文]
   

  層状金属カルコゲナイドは表面にダングリングボンドを持たず、さまざまな物性と仕事関数を持つ物質であるため、ナノ構造化によりデバイス応用が期待される。本発表では、我々が行っている流路分離型CVD成長による成長制御と、CNT等との複合材料化について報告する。
• 光機能性材料研究会セミナー 計算科学によるフレキシブル半導体材料の物性研究

  島田敏宏, XIE Wei, 山川貴恵, 柳瀬隆, 長浜太郎 日本写真学会誌 78 (4) 248 -250 2015年11月25日 [査読無し][通常論文]
   

  <p>フレキシブルエレクトロニクスの基礎研究のために変形に強い柔らかい半導体の特性に関する計算科学を用いた2つの研究例について報告する．まず，有機半導体に対する変形の一つとして板状結晶に対する圧縮と伸張の効果を分子動力学により扱い，次に，層状物質の例として六方晶窒化ホウ素（h-BN）に炭素をドープした物質の第一原理計算について述べる．</p>
• γ‐Al₂O₃エピタキシャル薄膜を用いたSiへのスピン注入素子の作製

  高橋望, 柳瀬隆, 長浜太郎, 島田敏宏 結晶成長国内会議予稿集(CD-ROM) 45th ROMBUNNO.20PS20 2015年10月19日 [査読無し][通常論文]
  
• 炭素ドープh‐BNの電子状態計算

  XIE Wei, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 76th ROMBUNNO.15P-2T-18 2015年08月31日 [査読無し][通常論文]
  
• 化学気相蒸着法によるNbS₂結晶薄膜の作製

  渡邉翔, WENG Mengting, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 76th ROMBUNNO.13P-1A-12 2015年08月31日 [査読無し][通常論文]
  
• ポリマー焼成法によるナノダイヤモンドの合成

  柳瀬隆, 長谷川幸樹, 上部宏晃, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 76th ROMBUNNO.14A-2Q-6 2015年08月31日 [査読無し][通常論文]
  
• 反応性MBE法によるエピタキシャルSn_xFe_3‐xO₄薄膜の作製

  荒木真人, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 39th 131 2015年08月25日 [査読無し][通常論文]
  
• CoFe₂O₄を用いた垂直磁化型スピンフィルター素子の作製

  梶田博樹, 柳瀬隆, 島田敏宏, 長浜太郎 日本磁気学会学術講演概要集 39th 169 2015年08月25日 [査読無し][通常論文]
  
• (CH)_nポリマーとAl₂O₃(0001)との反応によるAl₄C₃のエピタキシャル成長

  大見浩輔, 柳瀬隆, 長谷川幸樹, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 62nd ROMBUNNO.11A-D8-1 2015年02月26日 [査読無し][通常論文]
  
• 化学気相蒸着法による六角形NbS₂フレークの合成

  柳瀬隆, 渡邉翔, WENG Mengting, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 62nd ROMBUNNO.12P-D8-14 2015年02月26日 [査読無し][通常論文]
  
• ナノワイヤのCVD成長における酸化物基板上の核形成の影響

  島田敏宏, 川人愛子, 田村貴大, XIE W, 石岡準也, 柴山環樹, 渡辺精一, 柳瀬隆, 長浜太郎 セラミックス基礎科学討論会講演要旨集 53rd 204 2015年01月08日 [査読無し][通常論文]
  
• スピネルフェライト/Cr/Fe三層膜におけるFe層の保磁力の増大とCr膜厚依存性

  長浜太郎, 川井智博, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 76th 2015年
• エピタキシャルFe₃O₄/AlO_x/Feトンネル接合の伝導特性評価

  佐々木駿, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 39th 2015年
• 熱CVD法による酸化物基板上へのFeナノワイヤの作製

  川人愛子, 柳瀬隆, 石岡準也, 柴山環樹, 渡辺精一, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 75th ROMBUNNO.19P-PA4-3 2014年09月01日 [査読無し][通常論文]
  
• 層状金属カルコゲナイドのCVD:成長機構と自発的ナノ構造形成

  柳瀬隆, 渡辺翔, 橋本遊, 沓澤大, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 75th ROMBUNNO.18P-B3-6 2014年09月01日 [査読無し][通常論文]
  
• ダイヤモンドのプラズマCVD成長における固体挿入ドーピング

  田村貴大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 75th ROMBUNNO.17A-A8-6 2014年09月01日 [査読無し][通常論文]
  
• 有機薄膜形成過程の分子動力学シミュレーション

  島田敏宏, 田村貴大, 柳瀬隆, 長浜太郎 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 75th ROMBUNNO.17A-A5-1 2014年09月01日 [査読無し][通常論文]
  
• 熱CVD法による酸化物基板上へのFeナノワイヤの作製

  川人愛子, 柳瀬隆, 遠堂敬, 石岡準也, 柴山環樹, 渡辺精一, 長浜太郎, 島田敏宏 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 27th ROMBUNNO.2P036 2014年08月25日 [査読無し][通常論文]
  
• Fe₃O₄/Cr/Fe多層膜におけるFe層の磁化過程

  長浜太郎, 川井智博, 高橋望, 柳瀬隆, 島田敏宏 日本磁気学会学術講演概要集 38th 294 2014年08月19日 [査読無し][通常論文]
  
• CS-1-5 有機無機複合エレクトロニクスのための層状物質半導体微粒子の合成(CS-1.高性能有機デバイス開発に向けた有機エレクトロニクスの新展開,シンポジウムセッション)

  島田 敏宏 電子情報通信学会総合大会講演論文集 2014 (2) "S -8"-"S-9" 2014年03月04日
• 酸化物高指数表面の鉄ナノワイヤCVDに対する触媒機能

  島田敏宏, 川人愛子, 柳瀬隆, 長浜太郎 セラミックス基礎科学討論会講演要旨集 52nd 181 2014年01月09日 [査読無し][通常論文]
  
• ダイヤモンド前駆体ポリマーのグリニャール反応による合成

  大見浩輔, 柳瀬隆, 村谷直紀, 長浜太郎, 島田敏宏 応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集 49th-10th 66 2013年12月09日 [査読無し][通常論文]
  
• 触媒を用いた熱CVD法によるMoS_xナノワイヤの作製

  橋本遊, 沓澤大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会北海道支部・日本光学会北海道地区合同学術講演会講演予稿集 49th-10th 12 2013年12月09日 [査読無し][通常論文]
  
• Fabrication and Physical Properties of Organic Tricolor Superlattice

  Takashi Yanase, Toshihiro Shimada ELECTRONICS AND COMMUNICATIONS IN JAPAN 96 (12) 32 -36 2013年12月 [査読無し][通常論文]
   

  By combining the two concepts of superlattices and organic amorphous materials, we attempted to fabricate a new material that exhibits photo-switching piezoelectric properties. In order to utilize the merits of amorphous materials that can be deposited quickly, we started by building equipment specialized for the fabrication of organic amorphous superlattices. Using this equipment, we fabricated a p-type semiconductor/piezoelectric polymer/n-type semiconductor superlattice that responded to photoirradiation both electrically and mechanically. (c) 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(12): 32-36, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11556
• ダイヤモンド前駆体ポリマーのグリニャール反応による合成

  大見浩輔, 柳瀬隆, 村谷直紀, 長浜太郎, 島田敏宏 ダイヤモンドシンポジウム講演要旨集 27th 178 -179 2013年11月19日 [査読無し][通常論文]
  
• ダイヤモンド前駆体ポリマーの精密合成とその評価

  柳瀬隆, 村谷直紀, 大見浩輔, 島田敏宏 ダイヤモンドシンポジウム講演要旨集 27th 70 -71 2013年11月19日 [査読無し][通常論文]
  
• 熱CVD法によるFeナノワイヤの作製

  川人愛子, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 74th ROMBUNNO.18P-C11-13 2013年08月31日 [査読無し][通常論文]
  
• 熱CVD法によるMoS_xナノワイヤの作製

  橋本遊, 沓澤大, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会秋季学術講演会講演予稿集(CD-ROM) 74th ROMBUNNO.19P-P2-8 2013年08月31日 [査読無し][通常論文]
  
• ポリマー焼成法を用いたダイヤモンドの新規ドーピング手法の開発

  村谷直紀, 柳瀬隆, 大見浩輔, 長浜太郎, 島田敏宏 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 26th ROMBUNNO.2P060 2013年08月28日 [査読無し][通常論文]
  
• 熱化学気相蒸着法による鉄ナノワイヤーの作製

  柳瀬隆, 長浜太郎, 島田敏宏, 川人愛子 日本セラミックス協会秋季シンポジウム講演予稿集(CD-ROM) 26th ROMBUNNO.2P059 2013年08月28日 [査読無し][通常論文]
  
• 有機三色超格子による光応答するピエゾ薄膜の作製

  柳瀬 隆, 島田 敏宏 Molecular electronics and bioelectronics 24 (2) 97(35) -100(38) 2013年05月30日 [査読無し][通常論文]
  
• 蒸着で形成したC₆₀‐p型有機半導体接合の光電子分光による評価(2)

  土田裕也, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 60th ROMBUNNO.28P-G13-1 2013年03月11日 [査読無し][通常論文]
  
• 電気化学エッチングで作成したグラファイトエッジの評価

  久保田翔生, 柳瀬隆, 長浜太郎, 島田敏宏 応用物理学会春季学術講演会講演予稿集(CD-ROM) 60th ROMBUNNO.27A-G12-4 2013年03月11日 [査読無し][通常論文]
  
• 溶液合成した前駆体のMoS₂への変化過程

  島田敏宏, 橋本遊, 柳瀬隆, 長浜太郎, 米澤徹 応用物理学会春季学術講演会講演予稿集(CD-ROM) 60th ROMBUNNO.27P-G12-5 2013年03月11日 [査読無し][通常論文]
  
• CoFe₂O₄/Cr/Fe系の磁化過程のCr膜厚依存性

  川井智博, 平谷俊悟, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 37th 2013年
• MgO-MTJ/Pt/CoFe₂O₄の作製と磁気伝導特性

  高橋望, 平谷俊悟, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 37th 2013年
• Si上でのγ-Al₂O₃薄膜エピタキシャル成長とそのスピン特性

  渡辺雄介, 高橋望, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 37th 2013年
• CoCr₂O₄スピネルを用いたトンネル磁気抵抗素子の作製

  楯和也, 松田悠弥, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 37th 2013年
• CoFe₂O₄薄膜を用いた電圧誘起磁気異方性測定の試み

  平谷俊悟, 長浜太郎, 島田敏宏 日本磁気学会学術講演概要集 37th 2013年
• Orientation control and angle-resolved photoemission studies of organic epitaxial thin films on bismuth-terminated silicon surfaces

  Manabu Ohtomo, Yuya Tsuchida, Tetsuya Hasegawa, Toshihiro Shimada Journal of the Vacuum Society of Japan 56 (1) 1 -10 2013年 [査読無し][通常論文]
   

  The angle-resolved photoemission studies (ARPES) of organic semiconductors is the key to understand fundamental parameters in the carrier transport, such as transfer integrals, effective mass, and carrier-phonon coupling constant. The ARPES of organic semiconductors, however, requires well-defined, single-crystalline and highly conductive samples. Since organic semiconductors have extremely low conductivity with low symmetry unit cells, the number of ARPES research was limited, which was an obstruction to developing synthesis policy for high mobility materials. In this review, we will summarize one of the successful strategy for preparing quasi-singly-oriented and highly-conductive sample for ARPES. We will demonstrate that bismuth terminated silicon surface is an ideal surface to grow epitaxial organic films with practically important "standing" orientation. It was also confirmed that quasi-single crystalline film was grown by using vicinal surfaces and reducing surface symmetry. We will also present the band dispersion results with key parameters and discuss future prospects.
• 高品質Fe₃O₄エピタキシャル膜の構造及び磁気特性

  松田悠弥, 楯和也, 平谷俊悟, 渡辺雄介, 長浜太郎, 長浜太郎, 島田敏宏 応用物理学関係連合講演会講演予稿集(CD-ROM) 59th ROMBUNNO.17A-DP1-9 2012年02月29日 [査読無し][通常論文]
  
• 5-104 基礎課程の化学講義における演示実験の可能性 : 1〜2年生向けの化学熱力学・無機化学の例((01)基礎科目の講義・演習-I,口頭発表論文)

  島田 敏宏 工学教育研究講演会講演論文集 23 (59) 88 -89 2011年08月22日
• 三色超格子を用いた光スイッチング可能な圧電性薄膜の作製

  柳瀬隆, 長谷川哲也, 島田敏宏 応用物理学会学術講演会講演予稿集(CD-ROM) 72nd ROMBUNNO.1P-D-5 2011年08月16日 [査読無し][通常論文]
  
• Si表面修飾の最適化によるDBTTF薄膜の成長制御

  土田裕也, 大伴真名歩, 長浜太郎, 米沢徹, 島田敏宏 応用物理学会学術講演会講演予稿集(CD-ROM) 72nd ROMBUNNO.30A-V-9 2011年08月16日 [査読無し][通常論文]
  
• 有機半導体分子へのマイクロ波照射による新しい炭素固体の合成

  富田潤, 長浜太郎, 島田敏宏, 島田敏宏 応用物理学会学術講演会講演予稿集(CD-ROM) 72nd ROMBUNNO.31A-ZF-4 2011年08月16日 [査読無し][通常論文]
  
• 電気化学的還元によるグラファイト上でのグラフェンエッジの作製

  久保田翔生, 長浜太郎, 米澤徹, 島田敏宏 応用物理学会学術講演会講演予稿集(CD-ROM) 72nd ROMBUNNO.30P-ZT-1 2011年08月16日 [査読無し][通常論文]
  
• フラックス法による銅フタロシアニン結晶の作製

  生田裕, 土田裕也, 村谷直紀, 長浜太郎, 島田敏宏, 島田敏宏 応用物理学会学術講演会講演予稿集(CD-ROM) 72nd ROMBUNNO.30A-V-8 2011年08月16日 [査読無し][通常論文]
  
• 『ナノ結晶の成長と新機能』に寄せて(特集序文)

  島田 敏宏, 米澤 徹 日本結晶成長学会誌 37 (4) 265 -265 2011年01月 [査読無し][通常論文]
  
• 有機半導体における欠陥周囲の電子状態の計算化学的評価

  島田敏宏, 大伴真名歩, 柳瀬隆, 長谷川哲也 応用物理学会学術講演会講演予稿集(CD-ROM) 71st ROMBUNNO.15P-H-2 2010年08月30日 [査読無し][通常論文]
  
• 閉会の挨拶と今後の展望

  島田 敏宏 電気学会研究会資料. EFM, 電子材料研究会 2010 (1) 57 -58 2010年05月21日
• ガスバリア膜の精密・迅速評価装置の開発

  高橋 善和, 島田 敏宏, 管野 敏之 電子情報通信学会技術研究報告. OME, 有機エレクトロニクス 110 (59) 11 -14 2010年05月20日 

  We developed a novel apparatus for the measurement of the gas barrier properties of high barrier films. The measurement principle is based on the use of a low temperature trap to transfer the permeated vapor from the sample space under atmospheric pressure to the mass spectrometer situated in an ultrahigh vacuum. We have demonstrated that the sensitivity, dynamic range and lead time for the measurement can be significantly improved from those previously reported. It was revealed that the diffusion time in a polymer film must be considered in the measurement of high barrier films.
• Siを用いた電気二重層FET

  柳瀬隆, 島田敏宏, 長谷川哲也 応用物理学関係連合講演会講演予稿集(CD-ROM) 57th ROMBUNNO.19P-ZM-7 2010年03月03日 [査読無し][通常論文]
  
• 磁気円二色性によるC₆₀-Co化合物/Ni積層薄膜の界面磁気状態分光

  松本吉弘, 圓谷志郎, 島田敏宏, 楢本洋, 三谷誠司, 高梨弘毅, 高梨弘毅, 横山利彦, 境誠司 応用物理学会学術講演会講演予稿集(CD-ROM) 71st 2010年
• C₆₀-Co化合物/Ni積層薄膜における磁気交換結合

  松本吉弘, 圓谷志郎, 島田敏宏, 楢本洋, 三谷誠司, 高梨弘毅, 横山利彦, 境誠司 日本磁気学会学術講演概要集 34th 2010年
• 25pZK-3 有機半導体のエピタキシャル成長と温度可変・角度分解光電子分光(分光学的手法による有機薄膜研究の最先端,領域9,領域5,領域7合同シンポジウム,領域9,表面・界面,結晶成長)

  島田 敏宏 日本物理学会講演概要集 64 (2) 805 -805 2009年08月18日
• X-ray absorption spectroscopy and magnetic circular dichroism in codeposited C-60-Co films with giant tunnel magnetoresistance (vol 470, pg 244, 2009)

  Yoshihiro Matsumoto, Seiji Sakai, Yasumasa Takagi, Takeshi Nakagawa, Toshihiko Yokoyama, Toshihiro Shimada, Seiji Mitani, Koki Takanashi, Hiroshi Naramoto, Yoshihito Maeda CHEMICAL PHYSICS LETTERS 474 (1-3) 238 -238 2009年05月 [査読無し][通常論文]
  
• 30pTL-1 アナターゼ型Ti_<1-x>W_xO_2エピタキシャル薄膜の電気輸送特性と電子状態(30pTL Ti酸化物他,領域8(強相関系:高温超伝導,強相関f電子系など))

  竹内 詩人, 一杉 太郎, 鶴浜 哲一, 近松 彰, 組頭 広志, 尾嶋 正治, 廣瀬 靖, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 64 (1) 666 -666 2009年03月03日
• 軟X線磁気円二色性分光によるC₆₀-Co共蒸着薄膜のスピン状態解析

  松本吉弘, 境誠司, 圓谷志郎, 中川剛志, 高木康多, 横山利彦, 永松伸一, 島田敏宏, 楢本洋, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 日本磁気学会学術講演概要集 33rd 2009年
• 巨大トンネル磁気抵抗効果を示すC₆₀-Co共蒸着薄膜のスピン状態解析

  松本吉弘, 境誠司, 楢本洋, 中川剛志, 高木康多, 横山利彦, 島田敏宏, 三谷誠司, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 応用物理学関係連合講演会講演予稿集 56th (2) 2009年
• 巨大トンネル磁気抵抗効果に影響を及ぼすC₆₀-Co化合物の電子/スピン状態

  松本吉弘, 境誠司, 圓谷志郎, 中川剛志, 高木康多, 横山利彦, 永松伸一, 島田敏宏, 楢本洋, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 応用物理学会学術講演会講演予稿集 70th (2) 2009年
• 軟X線磁気円二色性分光によるC₆₀-Co共蒸着薄膜のスピン状態解析

  松本吉弘, 境誠司, 中川剛志, 高木康多, 横山利彦, 永松伸一, 島田敏宏, 楢本洋, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 分子科学討論会講演プログラム&要旨(Web) 3rd 2009年
• Carrier compensation mechanism of highly conductive anatase Ti 0.94Nb0.06O2 epitaxial thin films

  Hiroyuki Nogawa, Taro Hitosugi, Hideyuki Kamisaka, Kouichi Yamashita, Akira Chikamatsu, Kouhei Yoshimatsu, Hiroshi Kumigashira, Masaharu Oshima, Syoichiro Nadao, Yutaka Furubayashi, Yasushi Hirose, Toshihiro Shimada, Tetsuya Hasegawa Materials Research Society Symposium Proceedings 1074 41 -45 2008年12月01日 [査読無し][通常論文]
   

  We investigated electrical conduction of anatase Ti0.94Nb 0.06O2 (TNO) epitaxial thin films in relation to oxygen defects generated by post-annealing. Annealing of TNO in oxygen was found to cause dramatic decreases in ne. Resonant photoemission spectroscopy measurements revealed that a deep acceptor state just above the top of valence band evolves, synchronized with the decrease of ne. We proposed that the acceptor state originates from interstitial oxygen atoms combined with Nb dopants and compensates electron carriers. © 2008 Materials Research Society.
• 20aTA-5 絶縁物基板上のグラファイトのエピタキシャル成長(I)(20aTA グラフェン・グラファイトの形成と評価I,領域7(分子性固体・有機導体))

  島田 敏宏, 半澤 明範, 野口 卓也, 長谷川 哲也 日本物理学会講演概要集 63 (2) 726 -726 2008年08月25日
• 26pTD-12 超伝導Nb探針を用いたFI(Field Ion)-STM(表面界面電子物性,領域9,表面・界面,結晶成長)

  清水 亮太, 一杉 太郎, 福尾 則学, 村中 伸滋, 島田 敏宏, 橋詰 富博, 長谷川 哲也 日本物理学会講演概要集 63 (1) 909 -909 2008年02月29日
• C₆₀-Co薄膜の巨大トンネル磁気抵抗効果とスピン状態

  境誠司, 松本吉弘, 菅井勇, 三谷誠司, 高梨弘毅, 高梨弘毅, 高木康多, 中川剛志, 横山利彦, 島田敏宏, 前田佳均, 前田佳均 日本金属学会講演概要 143rd 2008年
• C₆₀-Co混合薄膜の電子・磁気状態の軟X線磁気円二色性分光

  松本吉弘, 境誠司, 楢本洋, 中川剛志, 高木康多, 横山利彦, 島田敏宏, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 応用物理学会学術講演会講演予稿集 69th (2) 2008年
• C₆₀-Coハイブリッド薄膜の電子・スピン状態と巨大トンネル磁気抵抗効果

  境誠司, 松本吉弘, 菅井勇, 三谷誠司, 高梨弘毅, 高梨弘毅, 高木康多, 中川剛志, 横山利彦, 島田敏宏, 楢本洋, 岡安悟, 前田佳均, 前田佳均 日本磁気学会学術講演概要集 32nd 2008年
• 巨大トンネル磁気抵抗効果トンネル磁気抵抗効果を示すC₆₀-Co共蒸着薄膜の電子・磁気状態

  松本吉弘, 境誠司, 楢本洋, 中川剛志, 高木康多, 横山利彦, 島田敏宏, 三谷誠司, 高梨弘毅, 高梨弘毅, 前田佳均, 前田佳均 分子科学討論会講演プログラム&要旨(Web) 2nd 2008年
• X線磁気円二色性測定によるC₆₀-Coナノ・グラニュラー薄膜の磁気特性解析

  松本吉弘, 境誠司, 楢本洋, 高木康多, 中川剛, 島田敏宏, 横山利彦, 前田佳均 ナノ学会大会講演予稿集 6th 2008年
• X線磁気円二色性測定によるC₆₀-Coナノ・グラニュラー薄膜の磁気特性解析

  松本吉弘, 境誠司, 楢本洋, 高木康多, 中川剛, 島田敏宏, 横山利彦, 前田佳均 ナノ学会大会講演予稿集 6th 2008年
• 有機半導体のグラフォエピタキシー

  池田 進, 和田恭雄, 稲葉克彦, 寺嶋和夫, 島田敏宏, 斉木幸一朗 日本結晶成長学会誌 35 (4) 243 -248 2008年 [査読無し][通常論文]
  
• アモルファス基板上における有機薄膜の面内配向制御：電界効果トランジスタへの応用に向けて

  池田 進, 和田恭雄, 島田敏宏, 斉木幸一朗 真空 50 (12) 729 -734 2007年12月 [査読無し][通常論文]
   

  Organic field effect transistors (OFETs) have attracted much attention as key devices to realize plastic electronics. Low mobility of OFETs is one of the major problems for practical use. To improve the mobility, fabrication technique of high quality organic semiconductor thin films is important. Surfaces of gate insulators are amorphous in many cases, so that a novel technique to control in-plane orientation on such amorphous substrates is urgently required. In this report, application of "graphoepitaxy" to control the in-plane orientation is proposed. The authors discovered that organic semiconductor α-sexithiophene grows with in-plane preferred orientation on artificial periodic grooves fabricated on thermally-oxidized silicon substrates. Using this technique, the test devices of OFETs with oriented 6T thin films were prepared. The mobility has not yet been improved owing to morphological problems of the thin films. A guide to the next step of research is presented based on current imaging by conductive atomic force microscopy.
  
• 22aXJ-4 ステップバンチング表面上にエピタキシャル成長したペンタセン単分子膜の構造と電子状態(表面界面構造,領域9,表面・界面,結晶成長)

  島田 敏宏, 大伴 真名歩, 長谷川 哲也 日本物理学会講演概要集 62 (2) 920 -920 2007年08月21日
• 21aRB-4 薄膜相ペンタセンのHOMOバンド分散測定(有機FET1,領域7,分子性固体・有機導体)

  大伴 真名歩, 鈴木 維允, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 62 (2) 846 -846 2007年08月21日
• 22pWF-2 アナターゼ型NbドープTiO_2の非金属-金属転移(Ti酸化物,電界効果,領域8,強相関係:高温超伝導,強相関f電子系など)

  一杉 太郎, 神坂 英幸, 山下 晃一, 近松 彰, 組頭 広志, 尾嶋 正治, 能川 玄之, 鶴浜 哲一, ホァン ゴク ラン フン, 中尾 祥一郎, 古林 寛, 笠井 淳平, 廣瀬 靖, 山田 直臣, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 62 (2) 600 -600 2007年08月21日 [査読無し][通常論文]
  
• 21aRJ-12 グラフォエピタキシーによる有機半導体薄膜の配向制御とFETへの応用(有機FET1,領域7,分子性固体・有機導体)

  池田 進, 和田 恭雄, 稲葉 克彦, 伊藤 義泰, 寺嶋 和夫, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 62 (1) 862 -862 2007年02月28日
• 18aTG-8 Nb探針によるSTM観察(表面界面電子物性,領域9,表面・界面,結晶成長)

  清水 亮太, 一杉 太郎, 福尾 則学, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 62 (1) 872 -872 2007年02月28日
• 19aZA-5 ポンププローブ法によるAlq_3分子内エネルギー移動の研究(超高速現象・非線形光学,領域5,光物性)

  宮田 敦彦, 小川 直毅, 田丸 博晴, 鈴木 維允, 島田 敏宏, 長谷川 哲也, 斉木 幸一朗, 宮野 健次郎 日本物理学会講演概要集 62 (1) 707 -707 2007年02月28日
• Spin injection from magnetic electrodes to organic semiconductors studied by transport and spectroscopic measurements

  SHIMADA Toshihiro Extended abstracts of the ... Conference on Solid State Devices and Materials 2006 306 -307 2006年09月13日
• 26pYF-2 ペンタセンと磁性金属の接合のXMCDおよび輸送特性測定(26pYF 分子素子,有機FET 2,領域7(分子性固体・有機導体))

  島田 敏宏, 阿部 仁, 能川 玄之, 大伴 真名歩, 清水 亮太, 雨宮 健太, 長谷川 哲也 日本物理学会講演概要集 61 (2) 714 -714 2006年08月18日
• 25aYC-11 有機グラフォエピタキシーの基板依存性から見たその成長機構(25aYC ナノチューブ・ナノワイヤ・結晶成長,領域9(表面・界面,結晶成長))

  池田 進, 筒井 謙, 江面 知彦, 稲葉 克彦, 伊藤 義泰, 寺嶋 和夫, 島田 敏宏, 和田 恭雄, 斉木 幸一朗 日本物理学会講演概要集 61 (2) 743 -743 2006年08月18日
• 26aYH-8 遷移金属をドープしたTiO_2エピタキシャル膜の磁場中XMCD測定(26aYH 領域3,領域9合同 表面・界面磁性,領域9(表面・界面,結晶成長))

  阿部 仁, 島田 敏宏, 能川 玄之, 雨宮 健太, 太田 俊明, 稲葉 和久, 廣瀬 靖, 古林 寛, 山本 幸生, 一杉 太郎, 松本 祐司, 長谷川 哲也 日本物理学会講演概要集 61 (2) 770 -770 2006年08月18日
• 26aYF-7 有機半導体のサブバンドギャップ励起特性(26aYF 分子素子,有機FET 1,領域7(分子性固体・有機導体))

  大伴 真名歩, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 61 (2) 706 -706 2006年08月18日
• 27pTD-6 低温STM/STS観測による局所擬ギャップ構造の温度依存性(27pTD 高温超伝導(トンネル分光),領域8(強相関系:高温超伝導,強相関f電子系など))

  眞嶋 秀樹, 村中 伸滋, 植田 敦希, 福尾 則学, 一杉 太郎, 島田 敏宏, 岡田 佳憲, 近藤 猛, 生田 博志, 松本 祐司, 長谷川 哲也 日本物理学会講演概要集 61 (1) 557 -557 2006年03月04日
• 28pRC-5 AlPcCl薄膜のin situ FET特性(28pRC 分子素子,領域7(分子性固体・有機導体))

  嘉治 寿彦, 島田 敏宏, 池田 進, 斉木 幸一朗 日本物理学会講演概要集 61 (1) 832 -832 2006年03月04日
• 28pRC-14 有機半導体界面におけるトラップのスピン偏極(28pRC 分子素子,領域7(分子性固体・有機導体))

  能川 玄之, 島田 敏宏, 斉木 幸一朗, 植田 敦希, 廣瀬 靖, 山本 幸生, 稲葉 和久, 笠井 淳平, 古林 寛, 一杉 太郎, 長谷川 哲也 日本物理学会講演概要集 61 (1) 834 -834 2006年03月04日
• 28aSC-4 遷移金属をドープしたTiO_2エピタキシャル膜のXAS,XMCD測定(28aSC 領域9,領域3合同 表面・界面磁性,領域9(表面・界面,結晶成長))

  阿部 仁, 島田 敏宏, 能川 玄之, 雨宮 健太, 太田 俊明, 稲葉 和久, 廣瀬 靖, 古林 寛, 山本 幸生, 一杉 太郎, 松本 祐司, 長谷川 哲也 日本物理学会講演概要集 61 (1) 873 -873 2006年03月04日
• Ferromagnetism in anatase TiO2codoped with Co and Nb

  T. Hitosugi, T. Hitosugi, T. Shimada, T. Shimada, T. Hasegawa, T. Hasegawa, G. Kinoda, K. Inaba, Y. Yamamoto, Y. Furubayashi, Y. Hirose Proceedings of the 8th International Symposium on Foundations of Quantum Mechanics in the Light of New Technology, ISQM-Tokyo 2005 191 -193 2006年01月01日 [査読無し][通常論文]
   

  Magneto-optical Faraday rotation angle of ferromagnetic anatase Co-doped TiO2films is enhanced and can be controlled by Nb doping. A carrier density of films can be varied by Nb doping in this room-temperature ferromagnetic degenerate semiconductor. A Ti0.89Nb0.06CO0.05O2film showed a Faraday rotation angle of 1.5 × 104deg/cm at 400 nm. An anomalous Hall effect, showing that the charge carriers are spin polarized, is observed in this film.
• New transparent conductors anatase Ti1-xMxO 2 (M=Nb,Ta): Transport and optical properties

  Yutaka Furubayashi, Taro Hitosugi, Taro Hitosugi, Yukio Yamamoto, Yasushi Hirose, Makoto Otani, Kiyomi Nakajima, Toyohiro Chikyow, Toshihiro Shimada, Toshihiro Shimada, Tetsuya Hasegawa, Tetsuya Hasegawa Materials Research Society Symposium Proceedings 905 13 -18 2005年12月01日 [査読無し][通常論文]
   

  We have discovered new transparent conducting oxides (TCOs), anatase Ti1-xMxO2 (M=Nb,Ta), in thin film form, Both films with 0.03 ≤ x ≤ 0.06 showed resistivity of 2-3 × 10 -4 Ωcm and internal transmittance of ∼95% in the visible light region (40 nm in thickness), at room temperature. These values are comparable to those of typical TCOs, such as In2-xSn xO3 (ITO). © 2006 Materials Research Society.
• 21aPS-13 走査型トンネル顕微鏡によるC_<60>薄膜の局所物性評価(領域9ポスターセッション,領域9(表面・界面,結晶成長))

  村中 伸滋, 一杉 太郎, 眞嶋 秀樹, 福尾 則学, 島田 敏宏, 長谷川 哲也 日本物理学会講演概要集 60 (2) 757 -757 2005年08月19日
• 21aXA-2 有機極性分子のin situ FET特性評価(有機FET,領域7(分子性固体・有機導体))

  嘉治 寿彦, 島田 敏宏, 吉川 元起, 斉木 幸一朗 日本物理学会講演概要集 60 (2) 702 -702 2005年08月19日
• 21aXA-7 有機薄膜FETのtime of flight移動度測定(2)(有機FET,領域7(分子性固体・有機導体))

  島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 60 (2) 703 -703 2005年08月19日
• 26pYK-6 有機FETのtime of flight移動度測定(FET,領域7(分子性固体・有機導体))

  山本 義朗, 島田 敏宏, 上野 啓司, 斉木 幸一朗 日本物理学会講演概要集 60 (1) 803 -803 2005年03月04日
• 22pYE-11 バッキーフェロセンエピタキシャル膜の低温STM観察(表面界面構造,領域9(表面・界面,結晶成長))

  島田 敏宏, 長谷川 哲也, 嘉治 寿彦, 斉木 幸一朗, 松尾 豊, 中村 栄一, 村中 伸滋, 福尾 則学, 眞嶋 秀樹, 一杉 太郎 日本物理学会講演概要集 60 (0) 793 -793 2005年 [査読無し][通常論文]
  
• 13pWH-2 有機 FET の光応答機構(FET, 領域 7)

  山本 義朗, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (2) 759 -759 2004年08月25日
• 13pWH-1 有機薄膜 FET の表面分光によるプラズマ振動の観測(FET, 領域 7)

  島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (2) 759 -759 2004年08月25日
• 13pWH-1 有機薄膜 FET の表面分光によるプラズマ振動の観測(FET, 領域 8)

  島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (2) 505 -505 2004年08月25日
• 13pWH-2 有機 FET の光応答機構(FET, 領域 8)

  山本 義朗, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (2) 505 -505 2004年08月25日
• 15aPS-63 超高真空・低温・磁場印加型磁気力顕微鏡 (MFM) の開発(領域 9)

  菅谷 英生, 一杉 太郎, 島田 敏宏, 長村 俊彦, 松本 祐司, 長谷川 哲也 日本物理学会講演概要集 59 (2) 838 -838 2004年08月25日
• 27pZP-1 有機薄膜トランジスタにおけるキャリヤの空間分布(領域7,領域8合同 分子デバイスII)(領域8)

  木口 学, 中山 学, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (1) 537 -537 2004年03月03日
• 27pZP-4 光照射によるC_<60>FET特性の変化(領域7,領域8合同 分子デバイスII)(領域8)

  山本 義朗, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (1) 538 -538 2004年03月03日
• 27pZP-4 光照射によるC_<60>FET特性の変化(領域7,領域8合同 : 分子デバイスII)(領域7)

  山本 義朗, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 59 (1) 837 -837 2004年03月03日
• 12aXF-6 バッキーフェロセンエピタキシャル薄膜の膜厚による構造変化(表面界面構造 : 金属・有機化合物, 領域 9)

  嘉治 寿彦, 島田 敏宏, 井上 宏昭, 松尾 豊, 國信 洋一郎, 中村 栄一, 斉木 幸一朗 日本物理学会講演概要集 59 (0) 783 -783 2004年 [査読無し][通常論文]
  
• 23aYC-11 メチル終端 Si(111) 表面の加熱による構造変化および電子分光測定

  宮寺 哲彦, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 58 (2) 830 -830 2003年08月15日
• 22pXG-2 ペンタセン薄膜における電界効果移動度の膜厚依存性

  木口 学, 中山 学, 藤原 宏平, 上野 啓司, 島田 敏宏, 斉木 幸一朗 日本物理学会講演概要集 58 (2) 752 -752 2003年08月15日
• 22pXG-10 C_<60> 薄膜 FET の紫外光電子分光

  島田 敏宏, 末次 徹, 山本 義朗, 宮寺 哲彦, 斉木 幸一朗 日本物理学会講演概要集 58 (2) 754 -754 2003年08月15日
• 25pPSB-17 Cu(100)上に作製したC_60薄膜の構造と電子状態(25pPSB 表面界面・結晶成長,領域9(表面・界面,結晶成長分野))

  飯泉 謙一, 木口 学, 島田 敏宏, 斉木 幸一朗, 小間 篤 日本物理学会講演概要集 57 (1) 839 -839 2002年03月01日
• 19aTF-12 メチル終端Si(111)表面の電子分光

  宮寺 哲彦, 飯泉 謙一, 島田 敏宏, 斉木 幸一朗, 小間 篤 日本物理学会講演概要集 56 (2) 745 -745 2001年09月03日
• 19aRH-3 (C_<60>, In)/Si(111)系における電子状態

  飯泉 謙一, 島田 敏宏, 斉木 幸一朗, 小間 篤 日本物理学会講演概要集 56 (2) 741 -741 2001年09月03日
• 17aTF-6 変調分子線散乱法を用いた微傾斜基板表面上での有機分子拡散過程の解析

  市川 央, 島田 敏宏, 小間 篤 日本物理学会講演概要集 56 (2) 719 -719 2001年09月03日
• 27pZ-10 ZnS系有機無機複合クラスター薄膜の電子分光

  上牟田 雄一, 島田 敏宏, 小間 篤 日本物理学会講演概要集 54 (2) 849 -849 1999年09月03日
• 24pY-17 変調分子線散乱法による有機分子の表面拡散過程の解析

  橋本 玲, 島田 敏宏, 小間 篤 日本物理学会講演概要集 54 (2) 795 -795 1999年09月03日
• 28a-YR-4 層状物質TaSe_2上のC_<60>超薄膜の電子分光

  上牟田 雄一, 島田 敏宏, 小間 篤 日本物理学会講演概要集 53 (2) 404 -404 1998年09月05日
• 26p-YR-3 変調分子線散乱法による有機分子・無機単結晶表面相互作用の測定

  小出 潤, 上牟田 雄一, 趙 庚娥, 島田 敏宏, 小間 篤 日本物理学会講演概要集 53 (2) 377 -377 1998年09月05日
• 25a-M-1 四角酸超薄膜におけるエピタキシャル圧

  杉浦 巌, 島田 敏宏, 小間 篤 日本物理学会講演概要集 53 (2) 280 -280 1998年09月05日
• 25p-R-5 分子線蒸着法により作製した液晶単分子膜の結晶構造

  永堀 真, 島田 敏宏, 小間 篤 日本物理学会講演概要集 53 (2) 845 -845 1998年09月05日
• 選択成長法による分子性結晶ナノ構造の形成

  上野 啓司, 島田 敏宏, 小間 篤 表面科学 19 (1) 14 -20 1998年01月10日
• 5a-YA-5 分子蒸着法による液晶単分子膜の作製とAFM観察

  永堀 真, 島田 敏宏, 小間 篤 日本物理学会講演概要集 52 (2) 833 -833 1997年09月16日
• 29p-PSB-28 有機分子エピタキシャル超薄膜の光吸収定量による昇温脱離

  平 博順, 島田 敏宏, 小間 篤 日本物理学会講演概要集. 秋の分科会 1995 (2) 502 -502 1995年09月12日
• 2p-J-8 TiSe_2超薄膜のエピタキシャル成長及び電気伝導度測定

  西川 洋行, 持田 陸宏, 島田 敏宏, 小間 篤 日本物理学会講演概要集. 秋の分科会 1994 (2) 113 -113 1994年08月16日
• 2p-J-9 TaSe_2エピタキシャル超薄膜の電気伝導

  持田 陸宏, 島田 敏宏, 小間 篤 日本物理学会講演概要集. 秋の分科会 1994 (2) 113 -113 1994年08月16日
• 28p-Y-12 TaS_2, TaSe_2 のエピタキシャル成長と電荷密度波

  島田 敏宏, 大内 二三夫, 小間 篤 秋の分科会講演予稿集 1992 (2) 518 -518 1992年09月14日

講演・口頭発表等

• MoS2のＣＶＤ成長－触媒ナノ粒子を用いたナノチューブ成長と薄膜の不純物・欠陥の解析  [招待講演]

  島田敏宏

  2018年日本表面真空学会学術講演会 2018年11月 口頭発表（招待・特別）
• フラックス蒸発法による有機半導体単結晶成長と応用  [招待講演]

  島田敏宏

  応用物理学会第79回秋季学術講演会 2018年09月 口頭発表（招待・特別）
• 有機半導体はどこまでフレキシブルか？ ― 計算と実験から考える(特別講演)  [招待講演]

  島田敏宏

  第２５回有機EL討論会 2017年11月 口頭発表（招待・特別）
• Synthesis of nanomaterials by chemical vapor deposition  [招待講演]

  島田敏宏

  The 53rd Summer Annual Conference of the Korean Vacuum Society International Symposium, Gangwon-do, Korea 2017年08月 口頭発表（招待・特別）

担当経験のある科目（授業）

大学院分析化学東京大学
化学熱力学北海道大学
化学I北海道大学
大学院 応用物質化学I（固体化学）北海道大学
無機化学「北海道大学」「東京大学」
物性化学北海道大学

共同研究・競争的資金等の研究課題

• 化学反応と相転移で電子を変える―質量ゼロの電子を含む有機伝導体の創製と未知の物性

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2027年03月 

  代表者 : 内藤 俊雄, 島田 敏宏
• 2次元物質単層シートの組成制御によるバンドギャップエンジニアリングの確立

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 柳瀬 隆, 島田 敏宏

産業財産権

• 特開2009-078963:有機半導体化合物の単結晶薄膜の作製方法  2009年04月16日

  加藤 隆志, 五十嵐 達也, 島田 敏宏, 石井 由威  富士フイルム株式会社, 国立大学法人 東京大学  200903079294827111
• 特開2005-281011:結晶性薄膜の作製方法及び装置  2005年10月13日

  島田 敏宏, 長谷川 哲也  財団法人神奈川科学技術アカデミー  200903026853738020
• 特開2004-315694:接着方法、接着剤、接着構造体、及び接着中間構造体  2004年11月11日

  島田 敏宏  国立大学法人 東京大学  200903031129079175
• 特許第2762046号:基板物質による成長速度の違いを利用した有機分子性物質高配向集合体の微細構造パターンの作成法  1998年03月27日

  島田 敏宏, 小間 篤  東京大学長  201103034790603767
• 特開平8-264445:基板物質による成長速度の違いを利用した分子性物質高配向集合体の微細構造パターンの作成法  1996年10月11日

  島田 敏宏, 小間 篤  東京大学長  200903004834796768
• 特許4759096:透過性測定装置および評価方法  

  島田敏宏