工学部

Takanori Aoki

  (青木 孝憲)

Profile Information

Affiliation
Lecturer, Department of Electrical, Electronic and Information Engineering, Osaka Sangyo University
Degree
工学士(大阪産業大学)

Researcher number
40268280
J-GLOBAL ID
200901021141928991
researchmap Member ID
5000043904

Papers

 77
  • Toshinobu Yasui, Takanori Aoki, Tatsuhiko Matsushita, Akio Suzuki, Masahiro Okuda
    Journal of the Vacuum Society of Japan, 53(5) 361-363, 2010  Peer-reviewed
    There are two advantageous points for fluorine-doped tin-oxide (FTO) films if used as transparent conducting electrodes the one is high average transmittance in the wave length region between 400 nm and 1500 nm which is favorable for thin film solar cells and the second is to improve anti-heat or anti-humidity properties of Al-doped zinc oxide (AZO) films when employed as a laminated structure of FTO and AZO layers. Therefore, approximately 500 nm-thick multi-layer transparent conducting films (FTO film (100 nm-thick) as protection layer/AZO film (400 nm-thick)) have been prepared. FTO films and AZO films were deposited at substrate temperature of 420~500°C and 280°C, respectively. Sheet resistance of 6.7μ/ P was obtained for the structure of FTO layer (fabricated at oxygen partial pressure of 0.5 Pa) and AZO layer (fabricated at oxygen partial pressure of 0 Pa).
  • Keita Nakamura, Takanori Aoki, Akio Suzuki, Tatsuhiko Matsushita, Masahiro Okuda
    IEEJ Transactions on Electronics, Information and Systems, 130(4) 633-636, 2010  Peer-reviewed
    In order to cope with the depletion of iudium, a strong interest has been recently turned to transparent conducting oxide (TCO) films based on a zinc oxide system. Focusing to this theme, it was tried to fabricate Gallium-doped zinc oxide (GZO) TCO films. But, it was difficult to make good films of GZO at low temperature. Therefore, it was tried to use laser-annealing-method for improved characteristics of GZO films. Approximately 200-nm-thick 5.0 wt.% Ga-doped zinc oxide (GZO: 5.0 wt.% Ga2O3) films have been deposited on glass substrates at Room Temperature by pulsed laser deposition (PLD) using the fourth harmonic generation (FHG) of Nd: YAG laser (λ=266 nm). In order to reduce resistivity of as-deposited films, annealing process was carried out by Nd:YAG (FHG) laser with laser energy density of 40 mJ/cm2. As a result, the resisivity was improved from 8.16 × 10-4 to 6.27 × 10-4 Ω•cm (improvement effect of 23.2 %). An average transmittance of ore than 85% in the visible region was obtained for the fabricated. © 2010, The Institute of Electrical Engineers of Japan. All rights reserved.
  • Toshimichi Kaminishi, Takanori Aoki, Tatsuhiko Matsushita, Akio Suzuki, Masahiro Okuda
    Journal of the Vacuum Society of Japan, 53(3) 203-205, 2010  Peer-reviewed
    Gallium-doped zinc oxide (GZO) thin films have been deposited on Cyclo-Olefin Polymer (COP) substrates at room temperature by pulsed laser deposition (PLD) using FHG of Nd: YAG laser (λ = 266 nm, 1.6 mJ/cm2) and then, thin films were annealed by pulsed laser with FHG of Nd: YAG laser (λ = 266 nm, 8-20 mJ/cm2) at room temperature. As a result, the resistivity was improved from 6.61 × 104 Ω.cm to 5.94 × 10-4 Ω-cm for films annealed at a laser energy density of 12 mJ/cm2.
  • Shinji Kaneda, Takanori Aoki, Tatsuhiko Matsushita, Akio Suzuki, Masahiro Okuda
    Journal of the Vacuum Society of Japan, 53(3) 200-202, 2010  Peer-reviewed
    Ultra-thin Ga203 doped zinc oxide transparent conduction films was deposited on glass substrates using pulsed laser deposition method by ArF excimer laser λ = 193 nm) at the substrate temperature from 180 to 260 0°C. The film thickness was changed from 40 to 110 nm-thick. The target containing 3 and 5 wt.% Ga2O3 were employed. As a result, resistivity of 2.69 × 10-4 Ω.cm was obtained for the film with 40 nm-thick fabricated using the target containing 5 wt.% Ga 2O3 at substrate temperature of 260°C.
  • Kimihiro IKUTA, Takanori AOKI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahiro OKUDA
    IEEJ Trans. EIS, 129(11), Nov, 2009  Peer-reviewed

Misc.

 6
  • Naoya ICHII, Toshimichi KAMINISHI, Takanori AOKI, Tatsuhiko MATSUSHITA, Akio SUZUKI, Masahiro OKUDA
    The 21th Symposium on Phase Change Optical Information Strage PCOS 2009, Nov, 2009  Peer-reviewed
  • Takanori AOKI, Akio SUZUKI, Kazuma MISHIRO, Tatsuhiko MATSUSHITA, Masahiro OKUDA
    The 21th Symposium on Phase Change Optical Information Storage PCOS 2008, 3-8, Nov, 2008  Peer-reviewed
  • Kazuma MISHIRO, Takanori AOKI, Tatsuhiko MAtsushita, Akio SUZUKI, Masahiro OKUDA
    Proceedings of the 19th Symposium on Phase Change Optical Information Storage PCOS 2007, 21-26, Nov, 2007  Peer-reviewed
  • Hideaki AGURA, Takanori AOKI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahiro OKUDA
    IEEJ Trans. EIS, 125(11) 1641-1645, 2005  
    Approximately 150 nm-thick Al-doped zinc oxide (AZO) films with c-axis orientation have been prepared on glass substrates by pulsed laser deposition (PLD) using a split target divided into AZO(Al2O3 : 1 wt.%) and AZO(Al2O3 : 2 wt.%), which resulted in the adjustment of film composition by changing the ratio (trace ratio) of the time required to irradiate each side of the target alternately by an ArF excimer laser (λ= 193 nm). The film deposition took place at a substrate temperature of 230 °C. The trace ratio of 1 : 1 was employed, resulting in the film component of AZO(Al2O3 : 1.5 wt.%). In order to improve the film flatness, D.C. voltage of 150 V was applied perpendicularly to the plume generated between the substrate and the target. As a results, fluctuation of film-thickness improved from 7.8 % for the case without applied voltage to 4.7 %, with applied voltage of 150 V. For the AZO film deposited by irradiating a pulsed laser beam of energy density of 1 J/cm2 at repetition frequency of 10 Hz, the lowest resistivity was 2.47×10-4 Ω·cm for the case without applied voltage and 2.59×10-4 Ω·cm with applied voltage of 150 V. An average transmittance of more than 85 % in the visible range were obtained for the AZO films fabricated with and without D.C. voltage of 150 V applied perpendicularly to the plume, providing useful functionality as TCO films in the visible range.
  • YASUI Mitsuhiro, AOKI Takanori, SUZUKI Akio, MATSUSHITA Tatsuhiko, OKUDA Masahiro
    IEEJ Transactions on Electronics, Information and Systems, 124巻, 11号, 2202-2207(11) 2202-2207, 2004  
    β-FeSi2 thin films were grown on Si(111) substrates by pulsed laser deposition (PLD) method using Nd: YAG Laser (λ = 1064 nm, laser energy = 50 mJ, laser energy density = 1.65 J/cm2, repetition frequency = 10 Hz). In the fabrication process, three targets of (a) Fe(5N), (b) FeSi2(3N) and (c) Fe(5N) + FeSi2(3N) were used. The β-FeSi2 thin films having best properties of crystallinity were obtained in the case of (c), in which the first layer as the template was formed with the target of Fe(5N) and then, on top of that, the second layer was deposited with the target of FeSi2(3N). At this time, it was found that by XRD measurement, the degree of crystallinity of the films of the case (c) in which the first layer was introduced as the template improved 1.4 times as much as compared with the case (a), and that by SEM and AFM observations, surface morphologies also improved. Moreover, it was found that by TEM obeservation, the β-FeSi2 thin grew uniformly along the direction of (220) or (202) from the interface of the Si substrate and the film to the free surface and that by EDS analysis, the compositions of Fe and Si were uniformly distributed.

Research Projects

 1

研究テーマ

 2
  • 研究テーマ(英語)
    酸化物光記録膜に関する研究
    キーワード(英語)
    酸化物、光記録膜
  • 研究テーマ(英語)
    透明導電膜に関する研究
    キーワード(英語)
    ZnO
    概要(英語)
    PLD法を用いてZnO系透明導電膜を作成し、低抵抗かつ高透光性を示す材料および成膜手法を開発する。