Research activity information

• Oct. 2024 神戸大学, 優秀若手研究者賞

  服部吉晃


• Jan. 2024 コニカミノルタ科学技術振興財団, コニカミノルタ画像科学奨励賞

  服部吉晃


• Nov. 2023 神戸大学, 工学部優秀教育賞

  服部吉晃


• Jun. 2023 応用物理学会, 第70回応用物理学会春季学術講演会Poster Award

  服部 吉晃, 谷口 尚, 渡邊 賢司, 北村 雅季


• Dec. 2019 第16回薄膜材料デバイス研究会, スチューデントアワード, フルオロベンゼンチオールを電極表⾯に修飾した有機薄膜トランジスタ

  濱野 凌, 藤田 宏樹, 木村 由⻫, 服部 吉晃, 北村 雅季


• Nov. 2018 第15回薄膜材料デバイス研究会, スチューデントアワード, フルオロベンゼンチオール修飾による金表面の制御と有機トランジスタ応用

  YOSHIOKA Takumi, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  Japan society


• Mar. 2016 応用物理学会, 第63回応用物理学会春季学術講演会講演奨励賞

  服部吉晃, 谷口 尚, 渡邊 賢司, 長汐 晃輔

• Photomask-driven selective oxidation and optical imaging of ultrathin gold oxide films on antireflective substrates

  Satoshi Tanigaki, Daiki Murata, Masatoshi Kitamura, Yoshiaki Hattori

  May 2025, Japanese Journal of Applied Physics

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Visualization of patterned alkanethiol monolayers on an antireflective substrate using a reflected-light microscope

  Daiki Murata, Satoshi Tanigaki, Masatoshi Kitamura, Yoshiaki Hattori

  Dec. 2024, Japanese Journal of Applied Physics

  [Refereed]

  Scientific journal


• Identification of exfoliated monolayer hexagonal boron nitride films with a digital color camera under white light illumination

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Masatoshi Kitamura

  Abstract Optical microscopy with white light illumination has been employed when obtaining exfoliated monolayer hexagonal boron nitride (1L hBN) films from a large number of randomly placed films on a substrate. However, real-time observation of 1L hBN using a color camera under white light illumination remains challenging since hBN is transparent in the visible wavelength range. The poor optical constant of 1L hBN films in microphotographs is significantly improved using a Si substrate coated with a SiN _x thin-film (SiN _x /Si). When observing hBN thin films on SiN _x /Si using a color digital camera in an optical microscope under white light illumination, the clarity of the captured color images depends on the thickness of the SiN _x film (d). For real-time direct observation, the d was optimized based on quantitative chromatic studies tailored to Bayer filters of a color image sensor. Through image simulation, it was determined that the color difference between 1L hBN and the bare substrate is maximized at d = 59 or 70 nm, which was experimentally verified. The SiN _x /Si with optimized d values visualized 1L hBN films without requiring significant contrast enhancement via image processing under white light illumination in real-time. Furthermore, the captured color photographs facilitate the reliable determination of the number of layers in few-layer hBN films using the contrast of the green channel of the images.

  IOP Publishing, Jun. 2024, Nanotechnology, 35(37) (37), 375704 - 375704

  [Refereed]

  Scientific journal


• Surface properties of an InGaZnO₄ layer with a monolayer formed using a phosphonic acid: wettability, work function, and thermal stability

  Yudai Kitano, Yoshiaki Hattori, Masatoshi Kitamura

  Abstract The surface properties of an InGaZnO₄ (IGZO) layer with a monolayer formed on the surface using octadecyl phosphonic acid (ODPA) or (1H, 1H, 2H, 2H-heptadecafluorodecyl) phosphonic acid (FDPA) were investigated. Surface roughness, wettability, and work function were investigated using atomic force microscopy, water contact angle measurement, and photoelectron yield spectroscopy, respectively. The reaction time of monolayer formation on an IGZO layer was discussed based on the measured contact angle. An ODPA-monolayer formed at a slightly higher rate than an FDPA-monolayer. The work function measurement provided an estimate of the density of the molecule in the monolayer. Furthermore, the measured contact angle was used to evaluate the thermal stability of a monolayer. The evaluation suggested that annealing above 500 K causes monolayer desorption for both ODPA- and FDPA-monolayers.

  IOP Publishing, Dec. 2023, Japanese Journal of Applied Physics, 63(1) (1), 01SP32 - 01SP32

  [Refereed]

  Scientific journal


• Antireflection Substrates for Determining the Number of Layers of Few-Layer Hexagonal Boron Nitride Films and for Visualizing Organic Monolayers

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Masatoshi Kitamura

  American Chemical Society (ACS), Oct. 2023, ACS Applied Nano Materials

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Identification of the monolayer thickness difference in a mechanically exfoliated thick flake of hexagonal boron nitride and graphite for van der Waals heterostructures

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Masatoshi Kitamura

  Abstract Exfoliated flakes of layered materials, such as hexagonal boron nitride (hBN) and graphite with a thickness of several tens of nanometers, are used to construct van der Waals heterostructures. A flake with a desirable thickness, size, and shape is often selected from many exfoliated flakes placed randomly on a substrate using an optical microscope. This study examined the visualization of thick hBN and graphite flakes on SiO₂/Si substrates through calculations and experiments. In particular, the study analyzed areas with different atomic layer thicknesses in a flake. For visualization, the SiO₂ thickness was optimized based on the calculation. As an experimental result, the area with different thicknesses in a hBN flake showed different brightness in the image obtained using an optical microscope with a narrow band-pass filter. The maximum contrast was 12% with respect to the difference of monolayer thickness. In addition, hBN and graphite flakes were observed by differential interference contrast (DIC) microscopy. In the observation, the area with different thicknesses exhibited different brightnesses and colors. Adjusting the DIC bias had a similar effect to selecting a wavelength using a narrow band-pass filter.

  IOP Publishing, May 2023, Nanotechnology, 34(29) (29), 295701 - 295701

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Reflected light microscopy of a gold oxide layer formed on a Au film by ultraviolet/ozone treatment

  Yoshiaki Hattori, Masatoshi Kitamura

  Elsevier BV, Jan. 2023, Thin Solid Films, 764, 139631 - 139631

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Enhancement of the contrast for a hexagonal boron nitride monolayer placed on a silicon nitride/silicon substrate

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Masatoshi Kitamura

  Abstract We propose a visualization technique for identifying an exfoliated monolayer hexagonal boron nitride (hBN) flake placed on a SiN_x/Si substrate. The use of a Si substrate with a 63 nm thick SiN_x film enhanced the contrast of monolayer hBN at wavelengths of 480 and 530 nm by up to 12% and −12%, respectively. The maximum contrast for the Si substrate with SiN_x is more than four times as large as that for a Si substrate with a ∼90 or ∼300 nm SiO₂ film. Based on the results of the reflectance spectrum measurement and numerical calculations, the enhancement is discussed.

  IOP Publishing, Aug. 2022, Applied Physics Express, 15(8) (8), 086502 - 086502

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Organic monolayers modified by vacuum ultraviolet irradiation for solution-processed organic thin-film transistors

  Satoshi Inoue, Yoshiaki Hattori, Masatoshi Kitamura

  A trimethylsilyl-monolayer modified by vacuum ultraviolet (VUV) light has been investigated for use in solution-processed organic thin-film transistors (OTFTs). The VUV irradiation changed a hydrophobic trimethylsilyl-monolayer formed from hexamethyldisilazane vapor into a hydrophilic surface suitable for solution processing. The treated surface was examined via water contact angle measurement and X-ray photoelectron spectroscopy. An appropriate irradiation of VUV light enabled the formation of a dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C₈-BTBT) film on a modified monolayer by spin-coating. Consequently, the C₈-BTBT-based OTFT with a monolayer modified for an optimal VUV irradiation time exhibited a field-effect mobility up to 4.76 cm² V⁻¹ s⁻¹. The partial monolayer modification with VUV can be adapted to a variety of solution-processes and organic semiconductors for prospective printed electronics.

  Corresponding, {IOP} Publishing, Jun. 2022, Japanese Journal of Applied Physics, 61({SE}) ({SE}), SE1012 - SE1012

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Visualization of a hexagonal boron nitride monolayer on an ultra-thin gold film via reflected light microscopy

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Masatoshi Kitamura

  Hexagonal boron nitride (h-BN) is an important insulating layered material for two-dimensional heterostructure devices. Among many applications, few-layer h-BN films have been employed as superior tunneling barrier films. However, it is difficult to construct a heterostructure with ultra-thin h-BN owing to the poor visibility of flakes on substrates, especially on a metallic surface substrate. Since reflectance from a metallic surface is generally high, a h-BN film on a metallic surface does not largely influence reflection spectra. In the present study, a thin Au layer with a thickness of ∼10 nm deposited on a Si substrate with a thermally grown SiO₂ was used for visualizing h-BN flakes. The thin Au layer possesses conductivity and transparency. Thus, the Au/SiO₂/Si structure serves as an electrode and contributes to the visualization of an ultra-thin film according to optical interference. As a demonstration, the wavelength-dependent contrast of exfoliated few-layer h-BN flakes on the substrate was investigated under a quasi-monochromatic light using an optical microscope. A monolayer h-BN film was recognized in the image taken by a standard digital camera using a narrow band-pass filter of 490 nm, providing maximum contrast. Since the contrast increases linearly with the number of layers, the appropriate number of layers is identified from the contrast. Furthermore, the insulating property of a h-BN flake is examined using a conductive atomic force microscope to confirm whether the thin Au layer serves as an electrode. The tunneling current through the h-BN flake is consistent with the number of layers estimated from the contrast.

  {IOP} Publishing, Feb. 2022, Nanotechnology, 33(6) (6), 065702 - 065702

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Chain-Length Dependence of Optical Properties for an Alkanethiol Monolayer on an Ultrathin Gold Film Revealed via Reflected Light Microscopy

  Yoshiaki Hattori, Hayato Takahashi, Naoki Ikematsu, Masatoshi Kitamura

  American Chemical Society ({ACS}), Jul. 2021, The Journal of Physical Chemistry C, 125(27) (27), 14991 - 14999

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Polarization Raman Imaging of Organic Monolayer Islands for Crystal Orientation Analysis.

  Toki Moriyama, Takayuki Umakoshi, Yoshiaki Hattori, Koki Taguchi, Prabhat Verma, Masatoshi Kitamura

  An organic semiconductor film made of diphenyl derivative dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DPh-DNTT) has high carrier mobility. However, this mobility may be greatly affected by the crystal orientation of the DPh-DNTT's first layer. Polarization Raman microscopy is widely used to quantitatively analyze the molecular orientation, and thus holds great potential as a powerful tool to investigate the crystal orientation of monolayer DPh-DNTT with high spatial resolution. In this study, we demonstrate polarization Raman imaging of monolayer DPh-DNTT islands for crystal orientation analysis. We found that the DPh-DNTT sample indicated a strong dependence of the Raman intensity on the incident polarization direction. Based on the polarization dependence, we developed an analytical method of determining the crystal orientation of the monolayer DPh-DNTT islands and experimentally confirmed that our technique was highly effective at imaging the islands' crystal orientation with a spatial resolution of a few hundred nanometers.

  Corresponding, Apr. 2021, ACS omega, 6(14) (14), 9520 - 9527, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Energy distribution of interface states generated by oxygen plasma treatment for control of threshold voltage in pentacene thin-film transistors

  Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  Dec. 2020, JOURNAL OF PHYSICS D-APPLIED PHYSICS, 53(50) (50), English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Crystal Orientation Imaging of Organic Monolayer Islands by Polarized Light Microscopy.

  Yoshiaki Hattori, Masatoshi Kitamura

  The initial stage of organic semiconductor film formation greatly affects the properties of films, which are used in organic devices including thin-film transistors and light-emitting diodes. Organic monolayer islands that are formed on a suitable substrate can be observed with a conventional optical microscope. Furthermore, the use of a polarized microscope allows the determination of the refractive index and crystal orientation of islands. Here, we report organic monolayer islands of 2,9-diphenyl-dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DPh-DNTT) deposited on a Si substrate with thermally grown SiO2 to investigate the crystal orientation of islands by polarized light microscopy. The observation of DPh-DNTT islands under polarized quasi-monochromatic light reveals that reflection intensity depends on both the crystal orientation and irradiation wavelength. A comparison between experimental and calculated reflection intensities provides an estimate of an anisotropic complex refractive index in the plane. The crossed-polarized microscopy image of a SiO2/Si substrate with DPh-DNTT islands shows that the contrast between the islands and SiO2 surface is sensitive to the angle between the polarizer and analyzer and depends on the direction of crystal orientation. The dependence of reflection contrast, which can be explained by the anisotropic extinction coefficient, is used to confirm crystal orientation.

  American Chemical Society (ACS), Aug. 2020, ACS applied materials & interfaces, 12(32) (32), 36428 - 36436, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Evaluation of organic metal-oxide-semiconductor capacitors based on a distributed constant circuit

  Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  Mar. 2020, JAPANESE JOURNAL OF APPLIED PHYSICS, 59(3) (3), 036503 - 036503, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Formation of a mixed monolayer on a gold surface using fluorobenzenethiol and alkanethiol

  Naoki Ikematsu, Hayato Takahashi, Yoshiaki Hattori, Masatoshi Kitamura

  Mar. 2020, JAPANESE JOURNAL OF APPLIED PHYSICS, 59(SD) (SD), SDDA09 - SDDA09, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Formation of a monolayer on a gold surface with high thermal stability using benzenedithiol

  Hayato Takahashi, Naoki Ikematsu, Yoshiaki Hattori, Masatoshi Kitamura

  Mar. 2020, JAPANESE JOURNAL OF APPLIED PHYSICS, 59(SD) (SD), SDDA03 - SDDA03, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Wide-range work function tuning in gold surfaces modified with fluorobenzenethiols toward application to organic thin-film transistors

  Takumi Yoshioka, Hiroki Fujita, Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  Mar. 2020, FLEXIBLE AND PRINTED ELECTRONICS, 5(1) (1), English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Nucleation Density and Shape of Submonolayer Two-Dimensional Islands of Diphenyl Dinaphthothienothiophene in Vacuum Deposition

  Yoshiaki Hattori, Yoshinari Kimura, Masatoshi Kitamura

  Jan. 2020, JOURNAL OF PHYSICAL CHEMISTRY C, 124(1) (1), 1064 - 1069, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• The growth mechanism and characterization of few-layer diphenyl dinaphthothienothiophene films prepared by vacuum deposition

  Yoshiaki Hattori, Yoshinari Kimura, Takumi Yoshioka, Masatoshi Kitamura

  Nov. 2019, ORGANIC ELECTRONICS, 74, 245 - 250, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Data on optical microscopy and vibrational modes in Diphenyl Dinaphthothienothiophene thin films

  Yoshiaki Hattori, Yoshinari Kimura, Takumi Yoshioka, Masatoshi Kitamura

  Oct. 2019, DATA IN BRIEF, 26, 104522 - 104522, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• A ring oscillator consisting of pentacene thin-film transistors with controlled threshold voltages

  Hajime Takahashi, Masatoshi Kitamura, Yoshiaki Hattori, Yoshinari Kimura

  Apr. 2019, JAPANESE JOURNAL OF APPLIED PHYSICS, 58(SB) (SB), SBBJ04, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Determination of Carrier Polarity in Fowler-Nordheim Tunneling and Evidence of Fermi Level Pinning at the Hexagonal Boron Nitride/Metal Interface

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio

  Apr. 2018, ACS APPLIED MATERIALS & INTERFACES, 10(14) (14), 11732 - 11738, English, International magazine

  [Refereed]

  Scientific journal


• Impact ionization and transport properties of hexagonal boron nitride in a constant-voltage measurement

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio

  Jan. 2018, PHYSICAL REVIEW B, 97(4) (4), 045425, English

  [Refereed]

  Scientific journal


• Electrical integrity and anisotropy in dielectric breakdown of layered h-BN insulator

  K. Nagashio, Y. Hattori, N. Takahashi, T. Taniguchi, K. Watanabe, J. Bao, W. Norimatsu, M. Kusunoki

  Electrochemical Society Inc., 2017, ECS Transactions, 79(1) (1), 91 - 97, English

  [Refereed]

  International conference proceedings


• Comparison of device structures for the dielectric breakdown measurement of hexagonal boron nitride

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio

  Dec. 2016, APPLIED PHYSICS LETTERS, 109(25) (25), 253111, English

  [Refereed]

  Scientific journal


• Anisotropic Dielectric Breakdown Strength of Single Crystal Hexagonal Boron Nitride

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio

  Oct. 2016, ACS APPLIED MATERIALS & INTERFACES, 8(41) (41), 27877 - 27884, English, International magazine

  [Refereed]

  Scientific journal


• Fully dry PMMA transfer of graphene on h-BN using a heating/cooling system

  T. Uwanno, Y. Hattori, T. Taniguchi, K. Watanabe, K. Nagashio

  Dec. 2015, 2D MATERIALS, 2(4) (4), 041002, English

  [Refereed]

  Scientific journal


• Layer-by-Layer Dielectric Breakdown of Hexagonal Boron Nitride

  Yoshiaki Hattori, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio

  Jan. 2015, ACS NANO, 9(1) (1), 916 - 921, English, International magazine

  [Refereed]

  Scientific journal


• Multifunctional Skin-Like Electronics for Quantitative, Clinical Monitoring of Cutaneous Wound Healing

  Yoshiaki Hattori, Leo Falgout, Woosik Lee, Sung-Young Jung, Emily Poon, Jung Woo Lee, Ilyoun Na, Amelia Geisler, Divya Sadhwani, Yihui Zhang, Yewang Su, Xiaoqi Wang, Zhuangjian Liu, Jing Xia, Huanyu Cheng, R. Chad Webb, Andrew P. Bonifas, Philip Won, Jae-Woong Jeong, Kyung-In Jang, Young Min Song, Beatrice Nardone, Michael Nodzenski, Jonathan A. Fan, Yonggang Huang, Dennis P. West, Amy S. Paller, Murad Alam, Woon-Hong Yeo, John A. Rogers

  Lead, Oct. 2014, ADVANCED HEALTHCARE MATERIALS, 3(10) (10), 1597 - 1607, English, International magazine

  [Refereed]

  Scientific journal


• Fractal design concepts for stretchable electronics

  Jonathan A. Fan, Woon-Hong Yeo, Yewang Su, Yoshiaki Hattori, Woosik Lee, Sung-Young Jung, Yihui Zhang, Zhuangjian Liu, Huanyu Cheng, Leo Falgout, Mike Bajema, Todd Coleman, Dan Gregoire, Ryan J. Larsen, Yonggang Huang, John A. Rogers

  Feb. 2014, NATURE COMMUNICATIONS, 5, 3266 - 3266, English, International magazine

  [Refereed]

  Scientific journal


• Synthesis of tungsten oxide, silver, and gold nanoparticles by radio frequency plasma in water

  Yoshiaki Hattori, Shinfuku Nomura, Shinobu Mukasa, Hiromichi Toyota, Toru Inoue, Tomoya Usui

  Nov. 2013, JOURNAL OF ALLOYS AND COMPOUNDS, 578, 148 - 152, English

  [Refereed]

  Scientific journal


• Electrical breakdown of microwave plasma in water

  Yoshiaki Hattori, Shinobu Mukasa, Hiromichi Toyota, Shinfuku Nomura

  Aug. 2013, CURRENT APPLIED PHYSICS, 13(6) (6), 1050 - 1054, English

  [Refereed]

  Scientific journal


• Synthesis of tungsten trioxide nanoparticles by microwave plasma in liquid and analysis of physical properties

  Yoshiaki Hattori, Shinfuku Nomura, Shinobu Mukasa, Hiromichi Toyota, Toru Inoue, Toshihiro Kasahara

  May 2013, JOURNAL OF ALLOYS AND COMPOUNDS, 560, 105 - 110, English

  [Refereed]

  Scientific journal


• Improvement in preventing metal contamination from an electrode used for generating microwave plasma in liquid

  Yoshiaki Hattori, Shinobu Mukasa, Hiromichi Toyota, Hiroshi Yamashita, Shinfuku Nomura

  Jan. 2012, SURFACE & COATINGS TECHNOLOGY, 206(8-9) (8-9), 2140 - 2145, English

  [Refereed]

  Scientific journal


• Continuous synthesis of magnesium-hydroxide, zinc-oxide, and silver nanoparticles by microwave plasma in water

  Yoshiaki Hattori, Shinobu Mukasa, Hiromichi Toyota, Toru Inoue, Shinfuku Nomura

  Dec. 2011, MATERIALS CHEMISTRY AND PHYSICS, 131(1-2) (1-2), 425 - 430, English

  [Refereed]

  Scientific journal


• Synthesis of zinc and zinc oxide nanoparticles from zinc electrode using plasma in liquid

  Yoshiaki Hattori, Shinobu Mukasa, Hiromichi Toyota, Toru Inoue, Shinfuku Nomura

  Jan. 2011, MATERIALS LETTERS, 65(2) (2), 188 - 190, English

  [Refereed]

  Scientific journal


• Growth of bubbles containing plasma in water by high-frequency irradiation

  Shinobu Mukasa, Tsunehiro Maehara, Shinfuku Nomura, Hiromichi Toyota, Ayato Kawashima, Yoshiaki Hattori, Yukio Hashimoto, Hiroshi Yamashita

  Jul. 2010, INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, 53(15-16) (15-16), 3067 - 3074, English

  [Refereed]

  Scientific journal


• Optimization and analysis of shape of coaxial electrode for microwave plasma in water

  Yoshiaki Hattori, Shinobu Mukasa, Shinfuku Nomura, Hiromichi Toyota

  Mar. 2010, JOURNAL OF APPLIED PHYSICS, 107(6) (6), 063305 - 063308, English

  [Refereed]

  Scientific journal


• Behavior of Bubbles and Surrounding Temperature of In-Liquid Plasma

  HATTORI Yoshiaki, MUKASA Shinobu, NOMURA Shinfuku, TOYOTA Hiromichi

  “In-liquid plasma” is generated inside the bubbles on the tip of an electrode by applying microwave radiation from the electrode. The in-liquid plasma on the tip of an electrode consists of a plasma generation region, vapor phase, bubble interface, and liquid phase. The growth of the bubble, including the plasma, in n-dodecane was observed using a high-speed camera. This was done because the pressure and the temperature surrounding the plasma needed to be clarified for utilizing it in such processes as chemical vapor deposition. The dependence of the bubble growth on the vessel pressure and on the microwave power was clarified, and the internal pressure of the bubbles was calculated by substituting the approximation curve of the observed bubble diameter in the Rayleigh-Plesset equation. The bubbles grow not continuously but intermittently as the plasma region expands and contracts. The growth of the bubbles increases with increase in the microwave power or decrease in the vessel pressure. The value of the internal pressure of the bubbles peaks between 200 and 600 hPa, it increases as the microwave power increases, and the effect of the vessel pressure on it is small. In addition, we measured the temperature surrounding the plasma using a thermocouple. The temperature can be measured vertically from the vapor phase to the liquid phase by moving the thermocouple in that direction. The point where the temperature measurable by the thermocouple reaches a maximum moves away from the tip of the electrode as the microwave power increases. The maximum temperature reaches the approximate saturation temperature of the liquid.

  Lead, The Heat Transfer Society of Japan, Oct. 2008, Thermal Science and Engineering, 47(201) (201), 131 - 137, Japanese

  [Refereed]

  Scientific journal

• 無反射多層基板を用いた光学的精密計測

  服部吉晃

  Single work, 月刊OPTRONICS (オプトロニクス社) 44(520), Apr. 2025


• Substrates for enhancing contrast in optical microscope images of layered materials.

  Yoshiaki Hattori

  Single work, JSAP Review(応用物理学会), 240406, 2024


• 透明な極薄膜を光学顕微鏡で観察するための無反射基板

  服部 吉晃

  光学 (日本光学会), 53, 256, 2024


• 層状物質の光学顕微鏡像におけるコントラストを増強するための基板

  服部 吉晃

  応用物理 (応用物理学会), 93, 231-235, 2024


• BNの絶縁性破壊強さの異方性とその起源

  Hattori Yoshiaki, Kosuke Nagashio

  Joint work, NEW DIAMOND, 133,19-24, 2019, Japanese

  Scholarly book


• 液中プラズマによるナノ粒子製造方法

  服部吉晃, 野村信福, 豊田洋通, 向笠忍

  ケミカルエンジニアリング (化学工業社), 57(7), 548-553, 2012

• 極薄膜イメージングのための有機単分子膜を用いた無反射基板の作製

  服部 吉晃, 北村 雅季

  第72回応用物理学会春季学術講演会, Mar. 2025


• 無反射多層基板を用いた極薄膜の検出と設計方法

  服部吉晃

  コニカミノルタカレッジ, Dec. 2024

  [Invited]


• 有機単分子膜による親水・疎水パターンの形成と無反射多層基板を用いた可視化

  佐藤 仁哉, 北村 雅季, 服部 吉晃

  応用物理学会関西支部 2024年度第２回講演会, Nov. 2024


• 無反射多層基板を用いた光学的精密計測

  服部吉晃

  JST-神戸大学 新技術説明会, Oct. 2024

  [Invited]


• 移動度 1 cm2 V-1 s-1 を超える SnOx pチャネル薄膜トランジスタ

  瀧 基紀, 二本木 崇桐, 服部 吉晃, 北村 雅季

  第43回電子材料シンポジウム, Oct. 2024


• 真空中および大気中で極薄膜InGaZnOトランジスタの電流電圧特性

  二本木 崇桐, 前田 拓海, 服部 吉晃, 北村 雅季

  第43回電子材料シンポジウム, Oct. 2024


• p チャネルSnOx 薄膜トランジスタのポストアニール効果

  瀧 基紀, 二本木 崇桐, 服部 吉晃, 北村 雅季

  第85回応用物理学会学術講演会, Sep. 2024


• 真空中における極薄膜InGaZnO トランジスタの電流電圧特性

  二本木 崇桐, 前田 拓海, 服部 吉晃, 北村 雅季

  第85回応用物理学会学術講演会, Sep. 2024


• 窒化膜付きシリコン基板を用いた単層hBNの観察

  服部 吉晃, 谷口 尚, 渡邊 賢司, 北村 雅季

  第71回応用物理学会春季学術講演会, Mar. 2024

  Oral presentation


• フォトマスクを用いた酸化金のパターニング形成

  谷垣 賢, 村田 大樹, 服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会第20回研究集会, Nov. 2023

  Poster presentation


• 光電子収量分光法によるIn7GaZnO13薄膜の仕事関数測定

  吉岡 賢司, 一楽 想大, 服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会第20回研究集会, Nov. 2023

  Poster presentation


• 二層構造InGaZnO4/In5GaZnO10から成る薄膜トランジスタの特性評価

  一楽 想大, 吉岡 賢司, 服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会第20回研究集会, Nov. 2023

  Poster presentation


• 光学顕微鏡を用いたチオール有機単分子膜のパターニング評価

  村田 大樹, 谷垣 賢, 服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会第20回研究集会, Nov. 2023

  Poster presentation


• 無反射多層基板を用いた二次元材料と有機単分子膜の可視化

  服部吉晃

  神戸大学大学院工学研究科先端膜工学研究拠点第9回ワークショップ, Oct. 2023

  [Invited]


• Coverage control of a phosphonic acid monolayer on an InGaZnO surface

  Yudai Kitano, Yoshiaki Hattori, Masatoshi Kitamura

  The 9th International Symposium on Organic and Inorganic Electronic Materials and Related Nanotecnologies (EM-NANO 2023), Jun. 2023

  Poster presentation


• 有機薄膜形成のためのインクジェット法による親水疎水パターニングを用いた液摘挙動制御

  津田 真太朗, 服部 吉晃, 井上 聡, 北村 雅季

  第70回応用物理学会春季学術講演会, Mar. 2023


• スパッタリングにより作製したIn5GaZnO10薄膜トランジスタの特性評価

  中野渡 俊喜, 渡邉 悠太, 服部 吉晃, 北村 雅季

  第70回応用物理学会春季学術講演会, Mar. 2023


• 層状物質の厚い膜に存在する単層分の厚さの違いを検知する手法

  服部 吉晃, 谷口 尚, 渡邊 賢司, 北村 雅季

  第70回応用物理学会春季学術講演会, Mar. 2023


• 大気中光電子収量分光法による原子比率の異なるInGaZnO 薄膜の仕事関数評価

  渡邉 悠太, 中野渡 俊喜, 服部 吉晃, 北村 雅季

  第83回応用物理学会秋季学術講演会, Sep. 2022


• In5GaZnO10薄膜トランジスタの特性評価

  中野渡 俊喜, 渡邉 悠太, 服部 吉晃, 北村 雅季

  第83回応用物理学会秋季学術講演会, Sep. 2022


• 塗布型有機薄膜トランジスタのためのUV/オゾン処理による有機単分子膜の改質

  井上 聡, 服部 吉晃, 北村 雅季

  第83回応用物理学会秋季学術講演会, Sep. 2022


• 六方晶窒化ホウ素の高電界下における電気伝導と絶縁破壊

  服部 吉晃

  第83回応用物理学会秋季学術講演会, Sep. 2022

  [Invited]


• 大気中光電子収量分光法によるInGaZnO薄膜のエネルギーバンド構造解析

  渡邉 悠太, 服部 吉晃, 北村 雅季

  第69回応用物理学会春季学術講演会, Mar. 2022

  Poster presentation


• 金極薄膜を用いた単層h-BNの可視化

  服部 吉晃, 谷口 尚, 渡邊 賢司, 北村 雅季

  第69回応用物理学会春季学術講演会, Mar. 2022

  Oral presentation


• Organic thin-film transistors for high performance logic circuits: Realization of short channel, high mobility, low contact resistance and threshold voltage control

  Masatoshi Kitamura, Yoshiaki Hattori

  2021 MRS FALL MEETING, Dec. 2021

  [Invited]


• Visualization of an alkanethiol monolayer via reflected light microscope

  服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会 第18回研究集会, Nov. 2021


• 塗布法による有機半導体薄膜の製膜において 2度塗りした際の薄膜形成メカニズム

  近藤隆介, 濱田拓巳, 服部吉晃, 北村雅季

  応用物理学会関西支部 2021年度第２回講演会, Oct. 2021


• 疎水性単分子膜を修飾した基板上への塗布法を用いた有機半導体薄膜形成技術

  濱田拓巳, 井上聡, 服部吉晃, 北村雅季

  応用物理学会関西支部 2021年度第２回講演会, Oct. 2021


• Organic monolayers modified by ultraviolet-ozone for solution-processed organic thin-film transistors

  Satoshi Inoue, Yoshiaki Hattori, Masatoshi Kitamura

  The International Conference on Flexible and Printed Electronics (ICFPE), Sep. 2021


• 光学顕微鏡による的異方性を持つ単分子有機薄膜の観察と画像処理解析

  津田 真太朗, 服部 吉晃, 北村 雅季

  応用物理学会関西支部 2021年度第１回講演会, Apr. 2021


• 光電子収量分法による酸素プラズマ処理したSiO2絶縁膜表面のエネルギー準位分析

  渡邉 悠太, 服部 吉晃, 北村 雅季

  応用物理学会関西支部 2021年度第１回講演会, Apr. 2021


• 撥水性基板上にスピンコート法を用いて作製した有機薄膜トランラジタの評価

  井上 聡, 服部 吉晃, 北村 雅季

  応用物理学会関西支部 2021年度第１回講演会, Apr. 2021


• Bottom-contact pentacene thin-film transistor with threshold voltages controlled by oxygen plasma treatment

  Hiroki Fujita, Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  IEEE EDS Kansai Chapter 第20回「関西コロキアム電子デバイスワークショップ」, Nov. 2020


• 酸素プラズマ処理により生じる有機半導体／ゲート絶縁膜界面準位のエネルギー分布

  木村 由斉, 服部 吉晃, 北村 雅季

  薄膜材料デバイス研究会 第17回研究集会, Nov. 2020


• Highly thermal-stable monolayers formed on a gold surface using benzenedithiol

  Hayato Takahashi, Naoki Ikematsu, Yoshiaki Hattori, Masatoshi Kitamura

  39th Electronic Materials Symposium, Oct. 2020


• Evaluation of carrier mobility in organic metal-oxide-semiconductor capacitors

  Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  39th Electronic Materials Symposium, Oct. 2020


• 偏光顕微鏡を用いた単層DPh-DNTT二次元核の方位決定

  服部 吉晃, 北村 雅季

  第67回応用物理学会春季学術講演会, Mar. 2020


• 酸素プラズマ処理が与える有機半導体/絶縁膜界面準位への影響

  木村 由斉, 服部 吉晃, 北村 雅季

  第67回応用物理学会春季学術講演会, Mar. 2020


• フルオロベンゼンチオールを電極表面に修飾した有機薄膜トランジスタ

  濱野 凌, 藤田 宏樹, 木村 由斉, 服部吉晃, 北村 雅季

  薄膜材料デバイス研究会 第16回研究集会, Nov. 2019


• Statistical study of shape for submonolayer 2D islands of DPh-DNTT prepared by vacuum deposition

  Yoshiaki Hattori, Yoshinari Kimura, Masatoshi Kitamura

  38th Electronic Materials Symposium, Oct. 2019


• 金表面に形成したベンゼンジチオール単分子膜の耐熱性評価

  高橋 勇人, 池松 直樹, 服部 吉晃, 北村 雅季

  第80回応用物理学会学術講演会, Sep. 2019


• MOSキャパシタ構造を利用した有機半導体中のキャリア移動度評価

  木村 由斉, 服部 吉晃, 北村 雅季

  第80回応用物理学会学術講演会, Sep. 2019


• 単層 DPh-DNTT の2次元アイランドにおける異方性

  服部 吉晃, 木村 由斉, 北村 雅季

  第80回応用物理学会学術講演会, Sep. 2019


• Bottom-contact pentacene thin-film transistor with threshold voltages controlled by oxygen plasma treatment

  Hiroki Fujita, Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  International Conference on Solid State Devices and Materials (SSDM), Sep. 2019


• 有機薄膜トランジスタにおける酸素プラズマを用いたパターニング

  鳥羽 哲平, 服部 吉晃, 北村 雅季

  応用物理学会関西支部 2019年度第１回講演会, Jun. 2019


• UV/ozone処理を用いた熱酸化膜上単分子膜の被覆率操作

  眞田 武, 北村 雅季, 服部 吉晃

  応用物理学会関西支部 2019年度第１回講演会, Jun. 2019


• The formation of a mixed monolayer on a gold surface toward surface property control

  Naoki Ikematsu, Hayato Takahashi, Yoshiaki Hattori, Masatoshi Kitamura

  10th International Conference on Molecular Electronics and Bioelectronics (M&BE 10), Jun. 2019


• High thermal stability of the benzenedithiol monolayer formed on a gold surface

  Hayato Takahashi, Ikematsu Naoki, Yoshiaki Hattori, Masatoshi Kitamura

  10th International Conference on Molecular Electronics and Bioelectronics (M&BE 10), Jun. 2019


• Surface properties of oriented polytetrafluoroethylene films with a micrometer pitch

  Yuki Matsuda, Yoshinari Kimura, Yoshiaki Hattori, Masatoshi Kitamura

  10th International Conference on Molecular Electronics and Bioelectronics (M&BE 10), Jun. 2019


• Voltage and frequency dependence of capacitance characteristics in organic MOS capacitors

  KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  Compound Semiconducotr Week (csw2019), May 2019, English, International conference

  Poster presentation


• Thin-film transistors based on copper phthalocyanine deposited on a gate dielectric rubbed with poly(tetrafluoroethylene)

  WATANABE Shotaro, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  Compound Semiconducotr Week (csw2019), May 2019, English, International conference

  Poster presentation


• Nucleation and shape of 2D islands of DPh-DNTT thin-films prepared by vacuum evaporation

  HATTORI Yoshiaki, KIMURA Yoshinari, KITAMURA Masatoshi

  Compound Semiconducotr Week (csw2019), May 2019, English, International conference

  Oral presentation


• 酸素プラズマ処理が与える有機半導体/絶縁膜界面準位への影響

  木村 由斉, 服部 吉晃, 北村 雅季

  第67応用物理学関係連合講演会, Mar. 2019


• 偏光顕微鏡を用いた単層DPh-DNTT二次元核の方位決定

  服部 吉晃, 北村 雅季

  第67応用物理学関係連合講演会, Mar. 2019


• 有機MOSキャパシタの電圧・周波数特性解析

  KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Domestic conference

  Oral presentation


• 真空蒸着法におけるDNTTとその誘導体の核形成機構

  HATTORI Yoshiaki, KIMURA Yoshinari, YOSHIOKA Takumi, KITAMURA Masatoshi

  第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Domestic conference

  Oral presentation


• 酸素プラズマ処理によるボトムコンタクト型有機トランジスタの閾値電圧制御

  FUJITA Hiroki, YOSHIOKA Takumi, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第66回応用物理学会春季学術講演会, Mar. 2019, Japanese, Domestic conference

  Poster presentation


• ポリテトラフルオロエチレン配向膜を有する銅フタロシアニン薄膜トランジスタ

  WATANABE Shotaro, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第15回薄膜材料デバイス研究会, Nov. 2018, Japanese, Domestic conference

  Poster presentation


• フルオロベンゼンチオール修飾による金表面の制御と有機トランジスタ応用

  YOSHIOKA Takumi, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第15回薄膜材料デバイス研究会, Nov. 2018, Japanese, Domestic conference

  Keynote oral presentation


• 有機薄膜トランジスタへの応用に向けたフルオロベンゼンチオール表面修飾による金電極の仕事関数制御

  YOSHIOKA Takumi, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第79回応用物理学会学術講演会, Sep. 2018, Japanese, Domestic conference

  Poster presentation


• 有機薄膜トランジスタにおける酸素プラズマ処理による閾値電圧シフトの起源

  TAKAHASHI Hajime, KITAMURA Masatoshi, HATTORI Yoshiaki, KIMURA Yoshinari

  第79回応用物理学会学術講演会, Sep. 2018, Japanese, Domestic conference

  Poster presentation


• 真空蒸着法におけるDPh-DNTT薄膜の成長機構

  HATTORI Yoshiaki, KIMURA Yoshinari, YOSHIOKA Takumi, KITAMURA Masatoshi

  第79回応用物理学会学術講演会, Sep. 2018, Japanese, Domestic conference

  Oral presentation


• Logic circuits consisting of pentacene thin-film transistors with controlled threshold voltages

  TAKAHASHI Hajime, KITAMURA Masatoshi, HATTORI Yoshiaki, KIMURA Yoshinari

  International Conference on Solid State Devices and Materials (SSDM), Sep. 2018, English, International conference

  Oral presentation


• Growth mechanism and electrical characterization of DPh-DNTT films prepared by vacuum deposition

  HATTORI Yoshiaki, KIMURA Yoshinari, YOSHIOKA Takumi, KITAMURA Masatoshi

  International Conference on Solid State Devices and Materials (SSDM), Sep. 2018, English, International conference

  Oral presentation


• Dielectric breakdown of h-BN and growth mechanism of DPh-DNTT

  HATTORI Yoshiaki

  2nd Bilateral Kobe-Kiel Workshop, Sep. 2018, English, International conference

  Oral presentation


• Thermal resistivity of copper phthalocyanine based thin-film transistors

  WATANABE Shotaro, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  3rd Bilateral Workshop on Research Exchange between National Taiwan University and Kobe University, Jul. 2018, English, International conference

  Poster presentation


• Layered materials for electronics

  HATTORI Yoshiaki

  3rd Bilateral Workshop on Research Exchange between National Taiwan University and Kobe University, Jul. 2018, English, International conference

  Oral presentation


• Electrode-surface modification for high-performance organic thin-film transistors

  YOSHIOKA Takumi, KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  3rd Bilateral Workshop on Research Exchange between National Taiwan University and Kobe University, Jul. 2018, English, International conference

  Poster presentation


• ボトムコンタクト型有機薄膜トランジスタにおける閾値電圧制御

  OISHI Momoko, KIMURA Yoshinari, TAKAHASHI Hajime, HANAFUSA Yuki, YOSHIOKA Takumi, HATTORI Yoshiaki, KITAMURA Masatoshi

  第65応用物理学関係連合講演会, Mar. 2018, Japanese, Domestic conference

  Poster presentation


• キャパシタンス測定による有機トランジスタの寄生抵抗評価

  KIMURA Yoshinari, HATTORI Yoshiaki, KITAMURA Masatoshi

  第65応用物理学関係連合講演会, Mar. 2018, Japanese, Domestic conference

  Oral presentation


• DPh-DNTT 薄膜トランジスタの遮断周波数測定

  服部 吉晃, 木村 由斉, 吉岡 巧, 髙橋 一, 北村 雅季

  第65回応用物理学会春季学術講演会, Mar. 2018, Japanese, Domestic conference

  Poster presentation


• Dielectric breakdown of layered insulator

  K. Nagashio, Y. Hattori, T. Taniguchi, K. Watanabe

  2016 COMPOUND SEMICONDUCTOR WEEK (CSW) INCLUDES 28TH INTERNATIONAL CONFERENCE ON INDIUM PHOSPHIDE & RELATED MATERIALS (IPRM) & 43RD INTERNATIONAL SYMPOSIUM ON COMPOUND SEMICONDUCTORS (ISCS), 2016, English, IEEE


• 1317 Study on gas production by microwave plasma in water-methanol mixture.

  KATOU Taichi, HATTORI Yoshiaki, MUKASA Shinobu, TOYOTA Hiromichi, NOMURA Shinfuku

  The Proceedings of Conference of Chugoku-Shikoku Branch, 2012, Japanese, The Japan Society of Mechanical Engineers


• 1314 Nanoparticles Continuous Synthesis Applying Microwave Plasma in Liquid and Effect of System Pressure

  Kasahara Toshihiro, Hattori Yoshiaki, Mukasa Shinobu, Usui Tomoya, Toyota Hiromiti, Nomura Shinhuku

  The Proceedings of Conference of Chugoku-Shikoku Branch, 2012, Japanese, The Japan Society of Mechanical Engineers


• 1407 An investigation of the suitable substrate for synthesizingdiamond by in-liquid plasma chemical deposition

  Toyota Hiromichi, Nomura Shinfuku, Hattori Yoshiaki, Kawashima Naoya, Mukasa Shinobu

  The Proceedings of Conference of Chugoku-Shikoku Branch, 2011, Japanese, The Japan Society of Mechanical Engineers


• 1408 An investigation ofthe optimum experimental condition forsynthesizing diamond by in-Iiquid plasma chemical deposition

  Toyota Hiromichi, Nomura Shinfuku, Hattori Yoshiaki, Watanabe Masahiro, Mukasa Shinobu

  The Proceedings of Conference of Chugoku-Shikoku Branch, 2011, Japanese, The Japan Society of Mechanical Engineers


• Nanoparticle Synthesis Applying Microwave Plasma in Liquid and Effect of Counter Plate

  Usui Tomoya, Hattori Yoshiaki, Mukasa Shinobu, Nomura Shinfuku, Toyota Hiromichi

  Proceedings of National Heat Transfer Symposium, 2011, Japanese, The Heat Transfer Society of Japan, 液体中で亜鉛の電極を利用しマイクロ波プラズマを発生させて電極を原料としたナノ粒子の合成を行った。エタノール中でプラズマを発生させると10-200nmの六角柱または球体の亜鉛ナノ粒子が合成され、純水中で発生させると亜鉛ナノ粒子と酸化亜鉛ナノ粒子が凝集した約200nmの花びら型をした粒子が合成された。また、電極上部に設置された金属プレートの直径と位置を変え、ナノ粒子の合成に及ぼす影響を調べた。ナノ粒子の合成速度は金属プレートの直径が大きいほど、位置が電極先端に近いほど大きくなった。投入電力が230Wの場合、合成速度は5g/hourとなった。さらに、銅の電極を利用し放電開始電力を調べた。放電開始電力は金属プレートの位置が近いほど小さくなった。


• 二層誘電体同軸型電極を利用したマイクロ波液中プラズマ

  服部吉晃, 向笠忍, 豊田洋通, 野村信福

  日本機械学会中国四国支部・九州支部合同企画講演会講演論文集, Oct. 2010, Japanese


• 液中プラズマ化学蒸着におけるプラズマ泡と基板の相互作用

  豊田洋通, 飯坂康介, 野村信福, 向笠忍, 服部吉晃

  日本機械学会中国四国支部・九州支部合同企画講演会講演論文集, Oct. 2010, Japanese


• Thermal Influence on Ignition Position of Microwave Plasma in Liquid

  Hattori Yoshiaki, Mukasa Shinobu, Nomura Shinfuku, Toyota Hiromichi

  Proceedings of National Heat Transfer Symposium, 2010, Japanese, The Heat Transfer Society of Japan, 純水中に発生するマイクロ波液中プラズマの点火位置を高速度カメラで観察した。また、3D-FDTD法を用いて電極表面の電界を計算し、マイクロ波によって加熱される液体が吸収する熱量を計算した。この熱量を使って電極周辺の液体の温度計算した結果、プラズマが発生する電極表面の電界強度の最も高い位置と、最も温度が高い位置は必ずしも一致しないことが明らかになった。また、実験から測定したプラズマの点火位置と数値計算によって求めた最も温度の高い地点が一致した。


• 403 Influence of Electrode Shape on Electrical Breakdown of Microwave In-liquid Plasma

  Hattori Yoshiaki, Nomura Shinfuku, Mukasa Shinobu, Toyota Hiromichi

  The Proceedings of Conference of Chugoku-Shikoku Branch, 2009, Japanese, The Japan Society of Mechanical Engineers


• Generation Pattern of Bubbles and Thermal Balance of Plasma in Water

  MUKASA Shinobu, MAEHARA Tsunehiro, NOMURA Shinfuku, TOYOTA Hiromichi, HATTORI Yoshiaki, MIYAKE Hiroyuki

  Proceedings of National Heat Transfer Symposium, 2009, Japanese, The Heat Transfer Society of Japan, 純水中に高周波を照射する電極を設置し，電極先端でプラズマを発生させる．高速度カメラでプラズマを内包する気泡の挙動を観察する．気泡の生成様式は，水温と供給電力により4つに分類され，加熱沸騰の場合との比較を行った．供給電力に対して，水温の上昇に消費される熱は約90%，蒸発として消費される熱は約10%，気泡表面から水中へと伝導される熱は約30%，さらに，化学反応により消費される熱は1%以下となることがわかった．


• Simultaneous Production of Hydrogen and CNTs by In-Liquid Plasma, and Its Discharge Characteristics

  Shinfuku Nomura, Hiromichi Toyota, Shinobu Mukasa, Yoshiaki Hattori, Yoshiyuki Takahashi, Naoharu Ueda, Hiroshi Yamashita, Muneo Tanaka

  HT2008: PROCEEDINGS OF THE ASME SUMMER HEAT TRANSFER CONFERENCE, VOL 1, 2009, English, AMER SOC MECHANICAL ENGINEERS, The plasma in liquid is generated by applying High-Frequency (HF) irradiation of 27.12 MHz or Microwave (MW) irradiation of 2.45 GHz from an electrode, namely, a monopole-antenna electrode inserted into a reactor vessel. n-dodecane, methanol, and water are used as test liquids. The glow discharge plasma can be kept in spite of atmospheric pressure due to the cooling effect of liquid itself The light emission from the plasma changes substantially according to the behavior of the bubble. The present Chemical Vapor Deposition (CVD) process also enabled simultaneous production of hydrogen gas and the synthesis of the Carbon Nano-Tubes (CNTs) in hydrocarbon liquids. The actual production of hydrogen per unit energy by this process corresponds to approximately 1% of that by conventional steam reforming method and about 32% of that by the alkaline water electrolysis. Moreover, this process can make the solid carbon of about 14 g/h at the same time.


• Behavior of Bubbles and Surrounding Temperature of In-Liquid Plasma

  Hattori Yoshiaki, Mukasa Shinobu, Nomura Shinfuku, Toyota Hiromichi

  Proceedings of National Heat Transfer Symposium, 2008, Japanese, The Heat Transfer Society of Japan, 液中プラズマは気相プラズマとは異なる特徴をもち，応用研究は活発に行われている．一方，基礎的な発生メカニズムや物性に関する研究報告は少ない．本研究では，プラズマ発生と同時に，プラズマを内包しながら発生し成長する泡の挙動を高速度ビデオカメラで撮影し，画像から気泡内部の圧力を求め，熱電対を用いてプラズマ周辺の温度を測定する．液中プラズマの気泡は系圧力が小さいほど大きく成長し，気泡が膨張，収縮する周期が長くなる．周辺温度はプラズマが消費するエネルギー量が大きく，系圧力が大きいほど上昇する．


• Behavior Characteristic of Microwave Plasma in an Organic Solvent

  服部吉晃, 向笠忍, 野村信福, 豊田洋通

  日本伝熱シンポジウム講演論文集(CD-ROM), 2007, Japanese


• Logic Circuits Consisting of Pentacene Thin-Film Transistors with Controlled Threshold Voltages

  H. Takahashi, M. Kitamura, Y. Hattori, Y. Kimura

  IEEE EDS Kansai Chapter 第19回「関西コロキアム電子デバイスワークショップ」

• 有機薄膜形成のための親水疎水パターニングを利用した液滴の動的制御

  服部 吉晃

  日本学術振興会, 科学研究費助成事業, 基盤研究(C), 神戸大学, Apr. 2024 - Mar. 2027


• その場観察法を用いた有機半導体薄膜の成長メカニズムの解明

  服部 吉晃

  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 神戸大学, Apr. 2021 - Mar. 2024

  フレキシブルデバイスやウェアラブルデバイスを実現するためには、熱に弱い柔軟なフィルム上にトランジスタを安価に作製する技術が必要である。近年、安価で大面積に有機トランジスタを作成する新しい手法として、有機溶媒に有機半導体材料を溶かした溶液をインクとして、印刷技術により基板に塗布し、有機半導体薄膜を製膜する手法が注目されている。この手法では基板に溶液を塗り広げて溶媒を乾燥させることで製膜するため、原理上、親水性の基板が望ましい。しかし、一般的に親水性基板の表面にはトランジスタのキャリア移動度を低下させるキャリアトラップが多数あることから、電子デバイスの観点としては疎水性基板が望ましく、これらを両立することは困難である。そこで、本研究では疎水性の基板を親水化するプロセスの処理時間に着目し、溶液の塗布が可能な最低限の処理を基板に行うことを提案し、検証した。撥水性基板として、絶縁膜の表面に有機単分子膜を製膜し、UVオゾン処理を行うことで親水化させる。有機薄膜はスピンコート法により溶液から製膜した。作製した薄膜を用いて有機トランジスタを作成し、電気特性の評価を行ったところ、UVオゾン処理時間を適切に制御することで、最大で4.76 cm2/(Vs)のキャリア移動度をもつ有機トランジスタが作製された。この値は過去の文献と比較しても、親水性基板を利用し、スピンコート法で作成されたトランジスタとしてはかなり高く、親水性かつトラップサイトの少ない、理想的な界面が形成された可能性がある。有機単分子膜の一部を親水化させる本手法は塗布型有機半導体トランジスタの作成において汎用的に適応可能な技術であり、実用化への貢献が期待される。


• Fundamental development for realization of high-performance organic transistors based on molecular orientation and interface control

  Kitamura Masatoshi

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, Apr. 2019 - Mar. 2022

  For improvement of the characteristics of organic transistors, we worked on the control of the gate insulator surface and the control of the organic semiconductor-metal interface. Regarding the control of the insulating film surface, the organic monolayer was appropriately surface-treated to enable the film formation process by the coating process, and the spin coating method achieved mobilities exceeding 4 cm2 / Vs. Regarding the control of the organic semiconductor-metal interface, we clarified the relationship between the organic monolayer and the work function, and found the organic monolayer appropriate for improvement of the characteristics in organic transistors. Regarding the control of the gate insulator surface, we reproduced the threshold voltage control by the surface treatment, and successfully estimated the density of the energy level generated by the treatment.


• Improvement of carrier mobility in polycrystalline organic semiconductor thin films

  Hattori Yoshiaki

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Early-Career Scientists, Kobe University, Apr. 2019 - Mar. 2021

  The quality of an organic film considerably affects the performance of electronic devices. Therefore, the characterization of organic films is an important issue for the realization of good electronic devices and for the preparation of ideal films. In this study, crystals of an organic thin film with a thickness of several nm are evaluated with an optical microscope under atmospheric pressure. By using the visualization technique, the growth mechanism of organic films was investigated.


• Improvement of permittivity of h-BN using super high-k layered dielectric for gate insulator

  Hattori Yoshiaki

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Young Scientists (B), Kobe University, Apr. 2017 - Mar. 2019, Principal investigator

  Hexagonal boron nitride (h-BN) is widely utilized as the substrate to achieve high carrier mobility in a graphene field effect transistor. However, the characteristic of low permittivity in h-BN requires high operating voltages in transistors. The problem can be solved by composite film with high-k and low-k dielectrics. However, the tunneling current goes through the gate insulator in the thin h-BN film as leakage current. However, little systematic study on the tunneling current and band alignment has been conducted for h-BN. We found that the polarity of tunneling current is hole, unlike general oxide material, because the Fermi levels of metals are pinned in the small energy range around 3.5 eV from the top of the conduction band of h-BN with Fermi level pinning.

  Competitive research funding


• Dielectric Breakdown of Hexagonal Boron Nitride Film for Gate Insulator

  Hattori Yoshiaki

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Research Activity Start-up, Grant-in-Aid for Research Activity Start-up, The University of Tokyo, Aug. 2014 - Mar. 2016

  Hexagonal boron nitride (h-BN) is considered as ideal substrate for 2D material devises. However, the reliability of insulating properties of h-BN itself has not been clarified yet. The anisotropic dielectric breakdown of h-BN has been studied. We have found that the dielectric breakdown in c axis direction using a conductive atomic force microscope proceeded in the layer-by-layer manner. The obtained dielectric field strength was ~12 MV/cm, which is comparable to the conventional SiO2. On the other hand, metal electrodes were fabricated on the h-BN surface to measure the dielectric field strength in a direction perpendicular to c axis. The dielectric field strength was estimated to be 3 MV/cm, which is the smaller than that in c axis direction.

• 光学顕微鏡像におけるコントラストを増強させるための無反射多層基板

  服部吉晃, 北村雅季

  特願2024-167598, 2024

  Patent right


• ナノ粒子製造装置、ナノ粒子製造方法、ナノ粒子、亜鉛/酸化亜鉛ナノ粒子および水酸化マグネシウムナノ粒子

  服部吉晃, 野村信福, 豊田洋通, 向笠忍

  特願2011-101531, 特許5874111, 2012

  Patent right


• 液中プラズマ発生装置および設計法

  服部吉晃, 野村信福, 豊田洋通, 向笠忍

  特願2009-017389, 2009, 特許5360966

  Patent right