Electron wave dynamics in ballistic transport device realized by BN and graphene system

• Project/Area Number: 15F15314
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 外国
• Research Field: Applied materials
• Research Institution: Chiba University
• Principal Investigator: 青木 伸之 千葉大学, 大学院工学研究院, 准教授 (60312930)
• Co-Investigator(Kenkyū-buntansha): CHUANG CHIASHAIN 千葉大学, 工学(系)研究科(研究院), 外国人特別研究員
• Project Period (FY): 2015-11-09 – 2018-03-31
• Project Status: Completed (Fiscal Year 2017)
• Budget Amount: ¥2,300,000 (Direct Cost: ¥2,300,000); Fiscal Year 2017: ¥600,000 (Direct Cost: ¥600,000); Fiscal Year 2016: ¥1,100,000 (Direct Cost: ¥1,100,000); Fiscal Year 2015: ¥600,000 (Direct Cost: ¥600,000)
• Keywords: グラフェン / 六方晶窒化ホウ素 / 量子伝導現象 / 化学気相成長法 / 走査ゲート顕微法 / エピタキシャルグラフェン / 化学気相成長法（CVD） / ドメイン境界 / グラフェン量子ドット / 磁気力顕微鏡 / プラズマエッチング / 窒化ホウ素（BN） / バリスティック伝導 / 磁気伝導度ゆらぎ / 窒化ホウ素

Outline of Annual Research Achievements

（１）化学気相成長（CVD）法で作製されたグラフェンに対して細線状に加工を行った試料を作製し、低温にて走査ゲート顕微法（SGM）による観察を行った。不規則性の強いCVDグラフェンであっても量子干渉効果が観測され、それらは磁場や電場およびホットキャリアによって変調可能であることを見出した。低磁場印加によるSGM像の変化に対しては弱局在現象と量子干渉効果に基づいて解析を進め、磁気振動から見積もられる干渉領域と広がりと、試料構造との関係を議論した。
（２）h-BN/単層グラフェン/h-BNサンドイッチ構造を有する試料の低温時期伝導現象を観測した。この構造により移動度は100,000 cm2/Vsまで劇的に上昇し、これにより準バリスティック伝導領域での量子干渉効果を議論することができるようになった。拡散伝導領域で観測されていたエルゴード理論（電場と磁場に対する伝導度ゆらぎが等価であるという理論）の破れが観測され、それがグラフェンにおける本質的な性質であることが示された。さらに磁場の印加により明瞭なシュブニコフ－ド・ハース振動が観測され、その解析からh-BN/グラフェン/h-BN系でのキャリアの位相緩和時間等について議論を行った。
（３）低キャリア密度のエピタキシャルグラフェンの低温磁気伝導について観測し、電子－電子相互作用による温度依存性や、バリアブルレンジホッピング伝導、電荷トラップ現象、化学ドーピングによる半導体／金属転移現象の観測に成功した。

Research Progress Status

29年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

29年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] 国立台湾大学/国立嘉儀大学/国立中興大学(台湾)
• [Int'l Joint Research] アリゾナ州立大学/ニューヨーク州立大学バッファロー校(米国)
• [Int'l Joint Research] 成均館大学(韓国)
• [Int'l Joint Research] 国立台湾大学/国立嘉儀大学/国立中興大学(台湾)
• [Int'l Joint Research] アメリカ標準局（NIST）/アリゾナ州立大学(米国)
• [Int'l Joint Research] 成均館大学(韓国)
• [Int'l Joint Research] 国立台湾大学/国立嘉儀大学(台湾)
• [Int'l Joint Research] 北京大学(中国)
• [Int'l Joint Research] 成均館大学(韓国)
• [Int'l Joint Research] 国立標準局(米国)
• [Journal Article] Hot carriers in CVD-grown graphene device with a top h-BN layer (2018)
  • Author(s): C. Chuang, M. Mineharu, N. Matsumoto, M. Matsunaga, C.-W. Liu, B.-Y. Wu, Gil-Ho Kim, L.-H. Lin, Y. Ochiai, K. Watanabe, T. Taniguchi, C.-T. Liang and N. Aoki
  • Journal Title: Journal of Nanomaterials Volume: 印刷中
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Large, non-saturating magnetoresistance in single layer chemical vapor deposition graphene with an h-BN capping layer (2018)
  • Author(s): Chiashain Chuang, C.-T. Liang, Gil-Ho Kim, R.E. Elmquist, Y. Yang, Y.P. Hsieh, Dinesh K. Patel, K. Watanabe, T. Taniguchi, and N. Aoki
  • Journal Title: Carbon Volume: 136 Pages: 211-216
  • DOI: 10.1016/j.carbon.2018.04.067
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Shubnikov-de Haas measurements on a high mobility monolayer graphene flake sandwiched between boron nitride sheets (2017)
  • Author(s): Naoki Matsumoto, Masaaki Mineharu, Masahiro Matsunaga,Chiashain Chuang, Yuichi Ochiai, Kenichi Oto, Gil-Ho Kim,Kenji Watanabe, Takashi Taniguchi, David K. Ferry, Carlo R. da Cunha and Nobuyuki Aoki
  • Journal Title: J. Phys.: Condens. Matter Volume: 29 Issue: 22 Pages: 225301-225301
  • DOI: 10.1088/1361-648x/aa6d36
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior (2016)
  • Author(s): C. R. da Cunha, M. Mineharu, M. Matsunaga, N. Matsumoto, C. Chuang, Y. Ochiai, G.-H. Kim, K. Watanabe, T. Taniguchi, D. K. Ferry, and N. Aoki
  • Journal Title: Scientific Reports Volume: 6 Issue: 1
  • DOI: 10.1038/srep33118
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Temperature dependence of electron density and electron-electron interactions in monolayer epitaxial graphene grown on SiC (2016)
  • Author(s): Chieh-Wen Liu, Chiashain Chuang, Yanfei Yang, Randolph E Elmquist, Yi-Ju Ho, Hsin-Yen Lee and Chi-Te Liang
  • Journal Title: 2D Materials Volume: 4 Issue: 2 Pages: 025007-025007
  • DOI: 10.1088/2053-1583/aa55b9
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Variable range hopping and nonlinear transport in monolayer epitaxial graphene grown on SiC (2016)
  • Author(s): Chieh-I Liu, Bi-Yi Wu, Chiashain Chuang, Ya-Chi Lee, Yi-Ju Ho, Yanfei Yang, Randolph E Elmquist, Shun-Tsung Lo, Chi-Te Liang
  • Journal Title: Semiconductor Science and Technology Volume: 31 Issue: 10 Pages: 105008-105008
  • DOI: 10.1088/0268-1242/31/10/105008
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Charge Trapping in Monolayer and Multilayer Epitaxial Graphene (2016)
  • Author(s): Chieh-I Liu, Pengjie Wang, Jian Mi, Hsin-Yen Lee, Chi Zhang, Xi Lin, Chiashain Chuang, Nobuyuki Aoki, Randolph E. Elmquist, and Chi-Te Liang
  • Journal Title: Journal of Nanomaterials Volume: 2016 Pages: 7372812-7372815
  • DOI: 10.1155/2016/7372812
  • Peer Reviewed / Open Access / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Imaging coherent transport in chemical vapor deposition graphene wide constriction by scanning gate microscopy (2016)
  • Author(s): Chiashain Chuang, Masahiro Matsunaga, Fan-Hung Liu, Tak-Pong Woo, Li-Hung Lin, Kenichi Oto, Yuichi Ochiai, Chi-Te Liang and Nobuyuki Aoki
  • Journal Title: Appl. Phys. Lett. Volume: 108 Issue: 12 Pages: 123105-123105
  • DOI: 10.1063/1.4944637
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Journal Article] Probing weak localization in chemical vapor deposition graphene wide constriction using scanning gate microscopy (2016)
  • Author(s): C. Chuang, M. Matsunaga, F-H. Liu, T-P. Woo, N. Aoki, L-H. Lin, B-Y. Wu, Y. Ochiai and C-T. Liang
  • Journal Title: Nanotechnology Volume: 27 Issue: 7 Pages: 075601-075601
  • DOI: 10.1088/0957-4484/27/7/075601
  • Peer Reviewed / Int'l Joint Research / Acknowledgement Compliant
• [Presentation] Study of plant leaf-derived grapheme quantum dots through magnetic force microscopy (2017)
  • Author(s): Chiashain Chuang, Masahiro Matsunaga, Prathik Roy, Rini Ravindranath, Huan-Tsung Chang, Chi-Te Liang, Nobuyuki Aoki
  • Organizer: 第64回応用物理学会春季学術講演会
  • Place of Presentation: パシフィコ横浜、神奈川県
  • Year and Date: 2017-03-14
• [Presentation] Investigation of plant leaf-derived graphene quantum dots via magnetic force microscopy (2017)
  • Author(s): Chiashain Chuang, Masahiro Matsunaga,Nobuyuki Aoki, Rini Ravindranath, Prathik Roy,
  • Organizer: 25th International Conference on Processing Fabrication of Advanced Materials
  • Place of Presentation: The University of Auckland, New Zealand
  • Year and Date: 2017-01-23
  • Int'l Joint Research / Invited
• [Presentation] Hot carriers in disordered grapheme with hexagonal-boron Nitride and multi-layer graphene (2017)
  • Author(s): C. Chuang, M. Mineharu1, N. Matsumoto, M. Matsunaga,C.-W. Liu, B.-Y. Wu, G.-H. Kim, L.-H. Lin, Y.Ochiai, K. Watanabe, T. Taniguchi, Dinesh Kumar, C.-T. Liang, N. Aoki
  • Organizer: EDISON20(The 20th International Conference on Electron Dynamics in Semiconductors)
  • Int'l Joint Research
• [Presentation] Thermal carriers in disorderedgrphene with hexagonal-Boron Nitride and multi-layer graphene (2017)
  • Author(s): Chuang Chiashain, Mineharu M., Matsunaga M., Liu C.-W., Wu B.-Y., Kim G.-H., Lin L.-H., Ochiai Y., Liang C.-T., Aoki N
  • Organizer: 日本物理学会2017年秋季大会
• [Presentation] Temperature-induced carrier redistribution in a CVD-grown grapheme wide constriction (2016)
  • Author(s): Chiashain Chuang, Che-Hsiu Hsueh, Tak-Pong Woo, Makoto Tsubota, Wenchin Wu, Yuichi Ochiai, Chi-Te Liang, Nobuyuki Aoki
  • Organizer: 日本物理学会2016年秋季大会
  • Place of Presentation: 金沢大学、石川県
  • Year and Date: 2016-09-13
• [Presentation] Imaging coherent transport in chemical vapor deposition graphene wide constriction using scanning gate microscopy (2016)
  • Author(s): Chiashain Chuang, Tak-Pong Woo, Fan-Hung Liu, Masahiro Matsunaga, Yuichi Ochiai, Chi-Te Liang and Nobuyuki Aoki
  • Organizer: 33rd International Conference on the Physics of Semiconductor (ICPS 2016)
  • Place of Presentation: Beijing, China
  • Year and Date: 2016-07-31
  • Int'l Joint Research
• [Presentation] Fabrication of e-beam-resist-free quasi-ballistic h-BN/graphene/h-BN electronic devices (2016)
  • Author(s): Chiashain Chuang, Masaaki Mineharu, Naoki Matsumoto, Masahiro Matsunaga, Yuichi Ochiai, Gil-Ho Kim, Chi-Te Liang, Randolph E. Elmquist, Nobuyuki Aoki
  • Organizer: 19th International Conference on Superlattices, Nanostructures and Nanodevices
  • Place of Presentation: Hong Kong, China
  • Year and Date: 2016-07-26
  • Int'l Joint Research
• [Presentation] Fabrication of e-beam-resist-free quasi-ballistic h-BN/graphene/h-BN electronic devices (2016)
  • Author(s): Chiashain Chuang, Mineharu Masaaki, Matsumoto Naoki, Masahiro Matsunaga, Yuichi Ochiai, Gil-Ho Kim, Nubuyuki Aoki
  • Organizer: 19th International Conference on Superlattices, Nanostructures and Nanodevices (ICSNN 2016)
  • Place of Presentation: Hong Kong (China)
  • Year and Date: 2016-07-25
  • Int'l Joint Research
• [Presentation] Thermal current-induced charge redistribution in wide CVD-grown grapheme constriction (2016)
  • Author(s): Chiashain Chuang, Tak-Pong Woo, Fan-Hung Liu, Masahiro Matsunaga, Yuichi Ochiai, Chi-Te Liang and Nobuyuki Aoki
  • Organizer: Compund Semiconductor Week(CSW2016)
  • Place of Presentation: Toyama International Conference Center, Japan
  • Year and Date: 2016-06-26
  • Int'l Joint Research
• [Presentation] Thermal current-induced charge redistribution in wide CVD-grown graphene constriction (2016)
  • Author(s): Chiashain Chuang, Tak-Pong Woo, Fan-Hung Liu, Masahiro Matsunaga, Yuichi, Ochiai, Chi-Te Liang and Nobuyuki Aoki
  • Organizer: Compound Semiconductor Week 2016 (CSW 2016)
  • Place of Presentation: Toyama International Conference Center
  • Year and Date: 2016-06-26
  • Int'l Joint Research
• [Presentation] Imaging coherent transport in chemical vapor deposition grapheme wide constriction by scanning gate microscopy (2016)
  • Author(s): Chianshain Chung, Masahiro Matsunaga, Fan-Hung Liu, Tak-Pong Woo, Li-Hung Lin, Bi-Yi Wu, Yuichi Ochiai, Chi-Te Liang, Nobuyuki Aoki
  • Organizer: 日本物理学会
  • Place of Presentation: 東北学院大学
  • Year and Date: 2016-03-19
• [Remarks] 千葉大学大学院先進理化学専攻物質科学コース・青木研究室
  • URL: http://adv.chiba-u.jp/nano/qnd/index.html
• [Remarks] 量子ナノデバイス研究グループ（青木研究室）
  • URL: http://adv.chiba-u.jp/nano/qnd/index.html