Extraordinary plasmon instabilities in graphene Dirac Fermions and their terahertz functional device applications

2018 Fiscal Year Annual Research Report

• Project/Area Number: 18H05331
• Allocation Type: Single-year Grants
• Research Institution: Tohoku University
• Principal Investigator: 尾辻 泰一 東北大学, 電気通信研究所, 教授 (40315172)
• Co-Investigator(Kenkyū-buntansha): 岩月 勝美 東北大学, 電気通信研究機構, 特任教授 (00590522) ; 佐藤 昭 東北大学, 電気通信研究所, 准教授 (70510410) ; 渡辺 隆之 東北大学, 電気通信研究所, 助教 (80771807)
• Project Period (FY): 2018-06-29 – 2022-03-31
• Keywords: グラフェン / プラズモン / 不安定性 / テラヘルツ

Outline of Annual Research Achievements

1. 非対称二重回折格子ゲート型グラフェントランジスタを研究代表者らが独自に開発してきたエピタキシャルグラフェン製膜
，グラフェン・窒化ホウ素剥離転写，グラフェンチャネルゲートスタック等のプロセス技術を駆使し，素子の設計・試作を行った．[担当：尾辻泰一，渡辺隆之（研究分担者），吹留博一（研究協力者）]
2. デバイスモデリングは，グラフェン電子正孔のクーロン相互作用に伴う多体効果をキャリア自己エネルギーとして記述し，GWA法およびランダム位相近似により線形バンド分散の崩れ（ブロードニングと非線形性）を伴うグラフェンプラズモンを定式化し，ポアッソン方程式と連立して自己無撞着に数値解析した．その結果，利得獲得のキラーとなるAuger過程はキャリア温度と強相関があり，キャリア温度を室温付近以下に保つことで大幅に抑止できることを見出した．[担当：尾辻泰一，佐藤昭（研究分担者）]
3. テラヘルツ帯の増幅現象を，研究代表者所有のテラヘルツ時間分解分光計測装置を用いて観測することに成功した．測定結果よりディラック点近傍までキャリアを枯渇化した場合のドリフト速度とプラズマ速度の同定を試みた結果，DC測定から同定される値から約一桁の乖離があることを見出した．直流測定で同定されるキャリア運動量緩和時間は光学測定から同定された値に比して一桁大きく，キャリア運動量緩和時間の周波数分散（本実験ではレッドシフト）が極めて大きいことを見出した．今後はその原因究明と，この分散効果がプラズモン不安定性に与える影響を理論実験両面から検証してゆく．[担当：尾辻泰一，渡辺隆之（研究分担者）]
4. 計画後半実施の第二の目的の計画遂行のための，調査研究・準備を進めた[担当：尾辻泰一，岩月勝美（研究分担者）]

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

・プラズモン異常不安定性の発現の根拠となるドリフト速度がプラズマ速度を超越する条件が実動作条件下で得られるか否かという本研究課題の核心に迫る実験を遂行し，これまで明確には認識されていなかったキャリア運動量緩和時間の周波数分散（レッドシフト）効果を発見した．実験ではテラヘルツ周波数帯のキャリア運動量緩和時間は直流動作時のそれに比して一桁短く，これは，キャリアのドリフト速度が一般常識に比して一桁遅いことを意味し，チェレンコフ（プラズモニックブーム）型の不安定性は発現し得ないことを意味する．得られたテラヘルツ帯増幅現象は，Dyakonov-Shurモデルによるドップラーシフト効果，およびRyzhii-Satou-Shurモデルによる速度変調効果に起因することを示唆するものであり，これらの不安定性によって室温下で9%という（グラフェン単層からの）巨大利得を獲得できたことは，驚きに値する．
・プラズモン不安定性発現機構の制御性を明らかにし，テラヘルツ帯コヒーレント発振源としての能力を定量的に明らかにしてゆくための礎を築けたことは，学術的に極めて有益な知見である．

Strategy for Future Research Activity

1. 試作した素子のテラヘルツ帯発振現象を研究代表者所有のフーリエ変換遠赤外分光計測装置を用いて測定し，テラヘルツ帯自励発振現象の室温観測を実現するとともに，自励発振特定のドレインバイアス，内部電界強度，キャリアドリフト速度に対する閾値特性を定量的に明らかにする[前年度からの継続課題]．
2. デバイスモデリングと素子の試作評価を通して，プラズモン異常不安定性が発現するためのデバイス・プロセス・材料物性パラメータへの要求条件を明らかにする[前年度からの継続課題]．
3. 運動量緩和時間の周波数分散の要因をグラフェン結晶依存のキャリア散乱過程やプラズモン減衰等のテラヘルツ周波数領域におけるキャリア散乱過程を念頭に置いて定量的に明らかにするとともに，不安定性発現機構の制御性を明らかにし，テラヘルツ帯コヒーレント発振源としての能力を定量的に明らかにしてゆく．
4. 実動作状態下におけるナノ領域のプラズモンダイナミクスの観測は，放射光施設Spring-8を利用したオペランド時間分解顕微分光計測装置を利用する[前年度からの継続課題]．
5. 計画後半実施の第二の目的の計画遂行のための，調査研究・準備を進める[前年度からの継続課題]．

Research Products

• [Int'l Joint Research] CNRS-Univ. Montpellier II(フランス)
  • Country Name: FRANCE
  • Counterpart Institution: CNRS-Univ. Montpellier II
• [Int'l Joint Research] Univ. Buffalo, SUNY/Rensselaer Polytechnic Inst.(米国)
  • Country Name: U.S.A.
  • Counterpart Institution: Univ. Buffalo, SUNY/Rensselaer Polytechnic Inst.
• [Int'l Joint Research] Salamanca Univ.(スペイン)
  • Country Name: SPAIN
  • Counterpart Institution: Salamanca Univ.
• [Int'l Joint Research] Inst. Microstructures for Phys., RAS/Kotelnikov Inst. Radio-Eng. Electron./Moscow Inst. Phys. Tech., RAS(ロシア連邦)
  • Country Name: RUSSIA FEDERATION
  • Counterpart Institution: Inst. Microstructures for Phys., RAS/Kotelnikov Inst. Radio-Eng. Electron./Moscow Inst. Phys. Tech., RAS
• [Journal Article] Terahertz light emission and lasing in current-driven graphenebased 2D nano-structures (2019)
  • Author(s): T. Otsuji
  • Journal Title: ISPlasma2019: 11th Int. Symp. on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials Abstracts Book Volume: 1 Pages: 18pC04I-1-2
  • Peer Reviewed
• [Journal Article] Graphene optoelectronics and plasmonics for terahertz device applications (2019)
  • Author(s): T. Otsuji
  • Journal Title: The 2nd Internatioal Workshop on 2D Materials A3 Foresight Program Abstracts Book Volume: 1 Pages: PL-1
  • Peer Reviewed
• [Journal Article] Graphene-based 2D-heterostructures for terahertz lasers and amplifiers (2019)
  • Author(s): D. Yadav, S. Boubanga-Tombet, A. Satou, T. Tamamushi, T. Watanabe, T. Suemitsu, H. Fukidome, M. Suemitsu, A. A. Dubinov, V. V. Popov, M. Ryzhii, V. Mitin, M. S. Shur, V. Ryzhii, T. Otsuji
  • Journal Title: Proc. SPIE Volume: 10917 Pages: 109170G-1-10
  • DOI: 10.1117/12.2516494
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Negative and positive terahertz and infrared photoconductivity in uncooled graphene (2019)
  • Author(s): V. Ryzhii, D.S. Ponomarev, M. Ryzhii, V. Mitin, M.S. Shur, and T. Otsuji
  • Journal Title: Opt. Mat. Exp. Volume: 9 Pages: 585-597
  • DOI: 10.1364/OME.9.000585
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Terahertz photoconductive emitter with dielectric-embedded high-aspect-ratio plasmonic grating for operation with low-power optical pumps (2019)
  • Author(s): D.V. Lavrukhin, A.E. Yachmenev, I.A. Glinskiy, R.A. Khabibullin, Y.G. Goncharov, M. Ryzhii, T. Otsuji, I.E. Spector, M. Shur, M. Skorobogatiy, K.I. Zaytsev, and D. Ponomarev
  • Journal Title: AIP Advances Volume: 9 Pages: 015112-1-5
  • DOI: 10.1063/1.5081119
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Terahertz current-driven plasmonic lasing and amplification (2018)
  • Author(s): D. Yadav, S. Boubanga-Tombet, G. Tamamushi, T. Watanabe, A. Satou, A. Dubinov, M. Ryzhii, V. Ryzhii, and T. Otsuji
  • Journal Title: WINDS 18: International Workshop on Innovative Nanoscale Devices and Systems Book of Abstracts Volume: 1 Pages: 72
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Plasmonic terahertz emitters with high-aspect raio metal gratings (2018)
  • Author(s): A. Yachmenev, D. Lavrukhin, L. Glinskiy, R. Khabibullin, R. Galiev, A. Pavlov, Yu. Goncharov, I. Spektor, M. Ryzhii, T. Otsuji, K. Zaytsev, and D. Ponomarev
  • Journal Title: ICMNE-2018: International Conference on Nano- and Micro-Electronics Book of Abstracts Volume: 1 Pages: 61
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Graphene-based 2D heterostructures for terahertz photonic and plasmonic light-sources applications (2018)
  • Author(s): D. Yadav, T. Watanabe, S. Boubanga-Tombet, A. Satou, V. Ryzhii, M. Ryzhii, A.A. Dubinov, W. Knap, V.V. Popov, T. Otsuji
  • Journal Title: ICMNE-2018: International Conference on Nano- and Micro-Electronics Book of Abstracts Volume: 1 Pages: 42
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Emission and amplification of terahertz radiation using Dirac fermions and plasmons in graphene (2018)
  • Author(s): T. Otsuji, D. Yadav, S. Boubanta-Tombet, T. Watanabe, A. Satou, A.A. Dubinov, M. Ryzhii, V.V. Popov, W. Knap, V. Mitin, M.S. Shur, and V. Ryzhii
  • Journal Title: RJUSE: the 7th Russia-Japan-USA-Europe Symposium on Fundamental & Applied Problems of Terahertz Devices & Technologies Dig. Volume: 1 Pages: 128-129
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Terahertz plasmon-emitting graphene-channel transistor (2018)
  • Author(s): A.A. Dubinov, V.Ya. Aleshkin, S.V. Morozov, V. Ryzhii, and T. Otsuji
  • Journal Title: RJUSE: the 7th Russia-Japan-USA-Europe Symposium on Fundamental & Applied Problems of Terahertz Devices & Technologies Book of Abstracts Volume: 1 Pages: 122-123
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Terahertz light amplification by instability-driven stimulated emission of graphene plasmon polaritons (2018)
  • Author(s): S. Boubanga-Tombet, D. Yadav, W. Knap, V. Popov, and T. Otsuji
  • Journal Title: IRMMW-THz: the 43rd International Conference on Infrared, Millimeter and Terahertz Waves Dig. Volume: 1 Pages: Tu-A2-R2-5
  • DOI: 10.1109/IRMMW-THz.2018.8510241
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] THz devices based on transistors incorporated with 2D plasmonic metamaterial structures (2018)
  • Author(s): A. Satou, M. Suzuki, T. hosotani, Y. Takida, H. Ito, H. Minamide, T. Suemitsu, and T. Otsuji
  • Journal Title: A3 Metamaterials Forum 2018 Dig. Volume: 1 Pages: I18
  • Peer Reviewed
• [Journal Article] Frequency-tunable terahertz light amplification by current-driven plasmon instabilities in graphene metamaterials (2018)
  • Author(s): W. Knap, S. Boubanga-Tombet, D. Yadav, V. Popov, T. Otsuji
  • Journal Title: ICPS: 34th International Conference on the Physics of Semiconductors Dig. Volume: 1 Pages: P1-114
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Terahertz light emission and lasing in graphene under current-injection pumping (2018)
  • Author(s): T. Otsuji, D. Yadav, S. Boubanta-Tombet, T. Watanabe, A. Satou, A.A. Dubinov, M. Ryzhii, V.V. Popov, W. Knap, V. Mitin, M.S. Shur, and V. Ryzhii
  • Journal Title: European Conf. on Lasers, Optics and Photonics, Dig. Volume: 1 Pages: 18
  • DOI: 10.21767/2349-3917-C1-001
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Graphene-channel-transistor terahertz amplifier (2018)
  • Author(s): S. Boubanga-Tombet, D. Yadav, W. Knap, V.V. Popov, and T. Otsuji
  • Journal Title: DRC: the 76th Annual Device Research Conference Dig. Volume: 1 Pages: 1-2
  • DOI: 10.1109/DRC.2018.8442272
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Graphene-based 2D heterostructure materials for terahertz photonics and plasmonics light-sources applications (2018)
  • Author(s): T. Otsuji
  • Journal Title: 2nd Global Summit & Expo on Laser Optics & Photonics 2018 Dig. Volume: 1 Pages: 1-2
  • Peer Reviewed
• [Journal Article] Terahertz light amplification by current-driven plasmon instabilities in graphene (2018)
  • Author(s): S. Boubanga-Tombet, D. Yadav, W. Knap. V.V. Papov, and T. Otsuji
  • Journal Title: CLEO: Int. Conf. on Lasers and Electro-Optics Dig. Volume: 1 Pages: SW4D.4-1-2
  • DOI: 10.1364/CLEO_SI.2018.SW4D.4
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Terahertz light emission and lasing in graphene-based vdW 2D heterostructures (2018)
  • Author(s): T. Otsuji
  • Journal Title: Journal of Nanomaterials & Molecular Nanotechnology Volume: 7 Pages: 59-60
  • DOI: 10.4172/2324-8777-C2-023
  • Peer Reviewed
• [Journal Article] Terahertz light emission and lasing in current-injection graphene-channel transistors (2018)
  • Author(s): D. Yadav, T. Watanabe, A. Satou, M. Ryzhii, V. Ryzhii, and T. Otsuji
  • Journal Title: 2nd Edition of Graphene & Semiconductors | Diamond, Graphite & Carbon Materials Conference Abstracts Volume: 1 Pages: 43
  • DOI: 10.4172/2169-0022-C3-097
  • Peer Reviewed
• [Presentation] Terahertz light emission and lasing in current-driven graphenebased 2D nano-structures (2019)
  • Author(s): T. Otsuji
  • Organizer: ISPlasma2019: 11th Int. Symp. on Advanced Plasma Science and its Applications for Nitrides and Nanomaterials, Nagoya Institute of Technology, Nagoya, Japan, March 18
  • Int'l Joint Research / Invited
• [Presentation] Terahertz photoconductive emitter with dielectricembedded high-aspect-ratio plasmonic grating for operation with low-power optical pumps (2019)
  • Author(s): D.S. Ponomarev
  • Organizer: iWAT: the International Workshop on Antenna Technology 2019, Florida International University (FIU) at the Graham Center, Miami, FL, USA, March 3
  • Int'l Joint Research
• [Presentation] Graphene-based van der Waals heterostructures towards a new type of quantum-cascade terahertz lasers (2019)
  • Author(s): T. Otsuji
  • Organizer: 1&2DM Conference and Exhibition, Tokyo Big-Site, Tokyo, Japan, Feb. 28
  • Int'l Joint Research / Invited
• [Presentation] Terahertz light emitting and lasing operation in graphene-based haterostructure 2D material systems (2019)
  • Author(s): T. Watanabe
  • Organizer: The 2nd Internatioal Workshop on 2D Materials A3 Foresight Program, Nanjing University, Nanging, China, Feb. 21
  • Int'l Joint Research
• [Presentation] Graphene optoelectronics and plasmonics for terahertz device applications (2019)
  • Author(s): T. Otsuji
  • Organizer: The 2nd Internatioal Workshop on 2D Materials A3 Foresight Program, Nanjing University, Nanging, China, Feb. 21
  • Int'l Joint Research / Invited
• [Presentation] Graphene-based 2D-heterostructures for terahertz lasers and amplifiers (2019)
  • Author(s): T. Otsuji
  • Organizer: SPIE Photonics West, Conference 10917: Terahertz, RF, Millimeter, and Submillimeter-Wave Technology and Applications XII, 10917-15, San Fransisco, CA, USA, Feb. 5
  • Int'l Joint Research / Invited
• [Presentation] グラフェンを利得媒質とするテラヘルツレーザー・増幅デバイス技術 (2018)
  • Author(s): 尾辻泰一
  • Organizer: URSI-C 小委員会 第24期 第3回公開研究会, 秋保温泉 緑水亭, 仙台, Dec. 14
  • Invited
• [Presentation] Terahertz current-driven plasmonic lasing and amplification (2018)
  • Author(s): T. Otsuji
  • Organizer: WINDS 18: International Workshop on Innovative Nanoscale Devices and Systems, Westin Hapuna Beach Resort, Hawaii, USA, Nov. 28
  • Int'l Joint Research / Invited
• [Presentation] Recent advances in 2D electronic and plasmonic terahertz devices utilizing graphenebased 2D materials (2018)
  • Author(s): T. Otsuji
  • Organizer: IEEE EDS Mini-Colloquium, Distinguished Lecture, IEEE Electron Device Society Spain Chapter, Hospederia Fonseca,Univ. Salamanca, Salamanca, Spain, Nov. 13
  • Int'l Joint Research / Invited
• [Presentation] Plasmon resonances in 2DEG and their applications to high-speed electron devices (2018)
  • Author(s): T. Otsuji
  • Organizer: IEEE EDS DL Public Lecture, IEEE EDS Japan Council Chapter, Ito Campus, Kyushu University, Fukuoka, Nov. 8
  • Int'l Joint Research / Invited
• [Presentation] 二次元プラズモン共鳴現象を用いたテラヘルツ素子の先駆的研究 (2018)
  • Author(s): 尾辻泰一
  • Organizer: 応用物理学会テラヘルツ電磁波技術研究会 第1回研究討論会「テラヘルツ波・高周波のデバイス・センシングの研究開発と応用」, JR博多シティ 10F会議室, 福岡, Nov. 7
  • Invited
• [Presentation] Recent advances in 2D electronic and plasmonic terahertz devices based on graphene-based 2D materials (2018)
  • Author(s): T. Otsuji
  • Organizer: IMESS: IEEE International Microwave, Electron Devices, & Solid-State Circuit Symposium 2018, PSDC, Penang, Malaysia, Oct. 10
  • Int'l Joint Research / Invited
• [Presentation] Plasmonic terahertz emitters with high-aspect raio metal gratings (2018)
  • Author(s): A. Yachmenev
  • Organizer: ICMNE-2018: International Conference on Nano- and Micro-Electronics, the Park-Hotel “Ershovo” in Zvenigorod, Moscow Region, Russia, Oct. 3
  • Int'l Joint Research
• [Presentation] Graphene-based 2D heterostructures for terahertz photonic and plasmonic light-sources applications (2018)
  • Author(s): T. Otsuji
  • Organizer: ICMNE-2018: International Conference on Nano- and Micro-Electronics, the Park-Hotel “Ershovo” in Zvenigorod, Moscow Region, Russia, Oct. 3
  • Int'l Joint Research / Invited
• [Presentation] Emission and amplification of terahertz radiation using Dirac fermions and plasmons in graphene (2018)
  • Author(s): T. Otsuji
  • Organizer: RJUSE: the 7th Russia-Japan-USA-Europe Symposium on Fundamental & Applied Problems of Terahertz Devices & Technologies, CBF Nowy Swiat, Warsaw, Poland, Sept. 21
  • Int'l Joint Research / Invited
• [Presentation] Terahertz plasmon-emitting graphene-channel transistor (2018)
  • Author(s): A.A. Dubinov
  • Organizer: RJUSE: the 7th Russia-Japan-USA-Europe Symposium on Fundamental & Applied Problems of Terahertz Devices & Technologies, CBF Nowy Swiat, Warsaw, Poland, Sept. 21
  • Int'l Joint Research
• [Presentation] Terahertz light amplification by instability-driven stimulated emission of graphene plasmon polaritons (2018)
  • Author(s): T. Otsuji
  • Organizer: IRMMW-THz: the 43rd International Conference on Infrared, Millimeter and Terahertz Waves, Nagoya, Aichi, Japan, Sept. 13
  • Int'l Joint Research
• [Presentation] Frequency-tunable terahertz light amplification by current-driven plasmon instabilities in graphene metamaterials (2018)
  • Author(s): W. Knap
  • Organizer: ICPS: 34th International Conference on the Physics of Semiconductors, Le Corum Palais des Congres, Montpellier, France, July 30
  • Int'l Joint Research
• [Presentation] Terahertz light emission and lasing in graphene under current-injection pumping (2018)
  • Author(s): T. Otsuji
  • Organizer: European Conf. on Lasers, Optics and Photonics, Prague, Czech Republic, July 16
  • Int'l Joint Research / Invited
• [Presentation] Graphene-channel-transistor terahertz amplifier (2018)
  • Author(s): T. Otsuji
  • Organizer: DRC: the 76th Annual Device Research Conference, UCSB, CA, USA, June 27
  • Int'l Joint Research
• [Presentation] Graphene-based 2D heterostructure materials for terahertz photonics and plasmonics light-sources applications (2018)
  • Author(s): T. Otsuji
  • Organizer: 2nd Global Summit & Expo on Laser Optics & Photonics 2018, Rome, Italy, June 15
  • Int'l Joint Research / Invited
• [Presentation] Terahertz light amplification by current-driven plasmon instabilities in graphene (2018)
  • Author(s): T. Otsuji
  • Organizer: CLEO: Int. Conf. on Lasers and Electro-Optics, San Jose, CA, USA, May 16
  • Int'l Joint Research
• [Presentation] Terahertz light emission and lasing in current-injection graphene-channel transistors (2018)
  • Author(s): T. Otsuji
  • Organizer: 2nd Edition of Graphene & Semiconductors | Diamond, Graphite & Carbon Materials Conference, Las Vegas, NV, USA, April 16
  • Int'l Joint Research / Invited
• [Remarks] Otsuji Laboratory
  • URL: http://www.otsuji.riec.tohoku.ac.jp/english/index_en.php