Elucidation of mechanism for low contact resistance in organic transistors and development of high speed device

• Project/Area Number: 26286037
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Applied materials
• Research Institution: Osaka University
• Principal Investigator: UEMURA TAKAFUMI 大阪大学, 産業科学研究所, 准教授 (30448097)
• Co-Investigator(Kenkyū-buntansha): 竹谷 純一 東京大学, 新領域創成科学研究科, 教授 (20371289) ; 岡本 敏宏 東京大学, 新領域創成科学研究科, 准教授 (80469931)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥15,990,000 (Direct Cost: ¥12,300,000、Indirect Cost: ¥3,690,000); Fiscal Year 2016: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000); Fiscal Year 2015: ¥6,110,000 (Direct Cost: ¥4,700,000、Indirect Cost: ¥1,410,000); Fiscal Year 2014: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
• Keywords: 接触抵抗 / 有機トランジスタ / フレキシブル / 有機エレクトロニクス / フレキシブルエレクトロニクス

Outline of Final Research Achievements

In this research, we developed a high-speed operation device with organic field-effect transistors (FETs). As a result, in the Au top contact organic FETs, we clarified that an annealing process dramatically reduces the contact resistance. Also, we clarified that the cause of the mobility overestimation of the organic FET is due to the large contact resistance. Moreover, by optimizing process conditions, we realized the world's smallest contact resistance (50 ohm・cm). Finally, we succeeded in fabricating a low voltage operating flexible organic FET circuit.

Research Products

• [Int'l Joint Research] imec(Belgium)
• [Journal Article] Ultraflexible and ultrathin polymeric gate insulator for 2 V organic transistor circuits (2016)
  • Author(s): M. Kondo, T. Uemura, T. Matsumoto, T. Araki, S. Yoshimoto, and T. Sekitani
  • Journal Title: Appl. Phys. Express Volume: 9 Issue: 6 Pages: 061602-061602
  • DOI: 10.7567/apex.9.061602
  • NAID: 210000137924
  • Peer Reviewed
• [Journal Article] Emergence of charge coherence in soft molecular organic semiconductors by suppressing thermal fluctuations (2016)
  • Author(s): K. Sakai, Y. Okada, T. Uemura, J. Tsurumi, R. Hausermann, H. Matsui, T. Fukami, H. Ishii, N. Kobayashi, K. Hirose and J. Takeya
  • Journal Title: NPG Asia Materials Volume: 8 Issue: 3 Pages: 252-252
  • DOI: 10.1038/am.2016.30
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] On the Extraction of Charge Carrier Mobility in High-Mobility Organic Transistors (2016)
  • Author(s): T. Uemura, C. Rolin, T.-H. Ke, P. Fesenko, J. Genoe, P. Heremans, and J. Takeya
  • Journal Title: Advanced Materials Volume: 28 Issue: 1 Pages: 151-155
  • DOI: 10.1002/adma.201503133
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Molecularly clean ionic liquid/rubrene single-crystal interfaces revealed by frequency modulation atomic force microscopy (2015)
  • Author(s): Y. Yokota, H. Hara, Y. Morino, K. Bando, A. Imanishi, T. Uemura, J. Takeya, K. Fukui
  • Journal Title: Phys. Chem. Chem. Phys. Volume: 17 Issue: 10 Pages: 6794-6800
  • DOI: 10.1039/c4cp06041e
  • Peer Reviewed
• [Journal Article] High-mobility organic transistors with wet-etch-patterned top electrodes: a novel patterning method for fine-pitch integration of organic devices (2014)
  • Author(s): K. Nakayama, M. Uno*, T. Uemura, N. Namba, Y. Kanaoka, T. Kato, M. Katayama, C. Mitsui, T. Okamoto, J. Takeya
  • Journal Title: Advanced Materials Interfaces Volume: in press Issue: 5
  • DOI: 10.1002/admi.201300124
  • Peer Reviewed
• [Journal Article] High-Performance Solution Processable N-Shaped Organic Semiconducting Materials with Stabilized Crystal Phase (2014)
  • Author(s): C. Mitsui, T. Okamoto*, M. Yamagishi, J. Tsurumi, K. Yoshimoto, K. Nakahara, J. Soeda, Y. Hirose, H. Sato, A. Yamano, T. Uemura, and J. Takeya*
  • Journal Title: Adv. Mater. Volume: - Issue: 26 Pages: 4546-4551
  • DOI: 10.1002/adma.201400289
  • Peer Reviewed / Open Access
• [Journal Article] Clean surface processing of rubrene single crystal immersed in ionic liquid by using frequency modulation atomic force microscopy (2014)
  • Author(s): Yasuyuki Yokota, Hisaya Hara, Yusuke Morino, Ken-ichi Bando, Akihito Imanishi, Takafumi Uemura, Jun Takeya, Ken-ichi Fukui
  • Journal Title: Applied Physics Letters Volume: 104 Issue: 26 Pages: 263102-263102
  • DOI: 10.1063/1.4886154
  • Peer Reviewed
• [Presentation] Biosignal Amplification Circuits Based on Ultra-Flexible Organic Thin-Film Transistors (2017)
  • Author(s): Takafumi Uemura and Tsuyoshi Sekitani
  • Organizer: International Thin-Film Transistor Conference, ITC2017
  • Place of Presentation: Austin, TX, USA
  • Year and Date: 2017-02-23
  • Int'l Joint Research / Invited
• [Presentation] Biological Signal Amplification Circuits Based on Organic Thin-Film Transistors (2016)
  • Author(s): Takafumi Uemura, Masaya Kondo, Toshikazu Nezu, Shusuke Yoshimoto, Teppei Araki, Kenichi Sasai, Tomoya Arai, Katsuyuki Morii, Tsuyoshi Sekitani
  • Organizer: International Conference on Flexible and Printed Electronics, ICFPE 2016
  • Place of Presentation: Yonezawa City, Yamagata, Japan
  • Year and Date: 2016-09-06
  • Int'l Joint Research
• [Presentation] Patterned Top-Contact Fabrication for Short-Channel Organic Transistors (2016)
  • Author(s): Takafumi Uemura
  • Organizer: The 16th International Meeting on Information Display, IMID 2016
  • Place of Presentation: ICC Jeju, Jeju, Korea
  • Int'l Joint Research / Invited
• [Presentation] High-Mobility Short-Channel Organic Transistors with Photolithography-Patterned Top Electrodes (2015)
  • Author(s): T. Uemura and T. Sekitani
  • Organizer: THE 22ND INTERNATIONAL DISPLAY WORKSHOPS (IDW '15)
  • Place of Presentation: Otsu, Japan
  • Year and Date: 2015-12-09
  • Int'l Joint Research / Invited
• [Presentation] Top Contact Lithography for High-Mobility Organic Transistors (2015)
  • Author(s): T. Uemura
  • Organizer: 2015 MRS Fall Meeting & Exhibit
  • Place of Presentation: Boston, Massachusetts, USA
  • Year and Date: 2015-11-29
  • Int'l Joint Research / Invited
• [Presentation] Recent Developments in High-Mobility Organic Field-Effect Transistors (2015)
  • Author(s): T. Uemura
  • Organizer: IEEE Custom Integrated Circuits Conference 2015
  • Place of Presentation: San Jose, CA, USA
  • Year and Date: 2015-09-28
  • Int'l Joint Research / Invited
• [Presentation] Nonlinear contact resistance in high performance organic thin film transistors (2015)
  • Author(s): Cedric Rolin, Takafumi Uemura, Jun Takeya, Jan Genoe, Paul Heremans
  • Organizer: The 2015 E-MRS Spring Meeting
  • Place of Presentation: Lille (France)
  • Year and Date: 2015-05-11 – 2015-05-15
• [Presentation] Gate-Voltage Dependence of Contact Resistance on High-Performance Organic Transistors (2014)
  • Author(s): T. Uemura, C. Rolin, P. Fesenko, T-H. Ke, K. Myny, S. Steudel, J. Genoe, P. Heremans and J. Takeya
  • Organizer: FET2014
  • Place of Presentation: 柏の葉カンファレンスセンター（千葉県、柏市）
  • Year and Date: 2014-10-17 – 2014-10-21
• [Presentation] 高移動度有機トランジスタにおける接触抵抗のゲート電圧依存性 (2014)
  • Author(s): 植村 隆文，Cedric Rolin，Pavlo Fesenko，Ke Tung Huei，Kris Myny，Soeren Steudel，Jan Genoe，Paul Heremans，竹谷 純一
  • Organizer: 第75回 秋季応用物理学会
  • Place of Presentation: 北海道大学札幌キャンパス（北海道、札幌市）
  • Year and Date: 2014-09-17 – 2014-09-20