Creation of ultrawide-bandgap-semiconductor exciton-engineering using deep-ultraviolet time and spatially resolved spectroscopies under extreme environments

• Project/Area Number: 19H02615
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 30010:Crystal engineering-related
• Research Institution: Kyoto University
• Principal Investigator: Ishii Ryota 京都大学, 工学研究科, 助教 (60737047)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000); Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2020: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000); Fiscal Year 2019: ¥11,180,000 (Direct Cost: ¥8,600,000、Indirect Cost: ¥2,580,000)
• Keywords: フォトルミネッセンス / エレクトロルミネッセンス / 窒化物半導体 / ダイヤモンド / 励起子 / 深紫外分光 / 近接場分光 / 極限環境下分光 / 束縛励起子 / AlGaN / 量子井戸 / 時間分解分光 / 超ワイドギャップ半導体 / 極限環境 / 顕微分光

Outline of Research at the Start

本研究の目的は，超ワイドギャップ半導体における励起子光物性の解明である．この研究目的を達成するために，極限環境下(極低温下・応力下・磁場下)における深紫外時空間分解分光法の利用を提案しているところに本研究の学術的独自性がある．

励起子とは，電子と正孔がクーロン相互作用によって結合した素励起状態のことである．超ワイドギャップ半導体中の励起子は光と強く相互作用するため，高効率発光/受光デバイスの創出が期待されているが実現には至っていない．この背景には，超ワイドギャップ半導体における励起子光物性の理解が不十分であることが問題点として挙げられる．本研究では，この問題点を解決し，励起子工学の創成を目指す．

Outline of Final Research Achievements

This study explored the excitonic properties of ultrawide bandgap semiconductors and the techniques of deep-ultraviolet time and spatially resolved spectroscopies under extreme environments. These include, unveiling that threading dislocations act as non-radiative recombination centers in blue-emitting LEDs at above room temperatures, first observation of deep-ultraviolet band-edge emission from nano-polycrystalline diamond, elucidating the internal quantum efficiency, current injection efficiency, and light extraction efficiency of AlGaN-based deep-ultraviolet LEDs, demonstration of deep-ultraviolet scanning near-field optical microscope with spatial resolution better than 100 nm, resolving the bound excitonic properties of n-type aluminum nitride.

Academic Significance and Societal Importance of the Research Achievements

波長200 nmから300 nmの深紫外光は，浄水やウイルスの不活化，ラベルフリー生体イメージング，および半導体微細加工技術などに大変有用である．超ワイドギャップ半導体は深紫外光源の1つとして注目されているが，現状超ワイドギャップ半導体を用いた深紫外光源の性能は低く留まっている．そこで本研究では，未だ成熟していない深紫外分光の深化とともに，深紫外分光を用いた超ワイドギャップ半導体の光物性解明に取り組み，深紫外光源の高性能化に繋がる超ワイドギャップ半導体の基礎光物性を明らかにすることに成功した．

Research Products

• [Int'l Joint Research] TU Berlin(ドイツ)
• [Journal Article] Stimulated emission mechanism of aluminum nitride (2022)
  • Author(s): R. Ishii, T. Nagashima, R. Yamamoto, T. Hitomi, M. Funato, and Y. Kawakami
  • Journal Title: Phys. Rev. B Volume: 105 Issue: 20 Pages: 1-9
  • DOI: 10.1103/physrevb.105.205206
  • Peer Reviewed
• [Journal Article] Microscopic origin of thermal droop in blue-emitting InGaN/GaN quantum wells studied by temperature-dependent microphotoluminescence spectroscopy (2021)
  • Author(s): R. Ishii, Y. Koyama, M. Funato, and Y. Kawakami
  • Journal Title: Optics Express Volume: 29 Issue: 15 Pages: 22847-22854
  • DOI: 10.1364/oe.428421
  • Peer Reviewed / Open Access
• [Journal Article] Structural and emission improvement of cyan-emitting InGaN quantum wells by introducing a large substrate misorientation angle (2021)
  • Author(s): A. Kafar,A. Sakaki,R. Ishii,K. Shojiki,S. Stanczyk,K. Gibasiewicz,G. Staszczak,L. Marona,D. Schiavon,S. Grzanka,S. Krukowski,T. Suski,P. Perlin,M. Funato,Y. Kawakami
  • Journal Title: Optical Materials Express Volume: 12 Issue: 1 Pages: 119-135
  • DOI: 10.1364/ome.445043
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Impact of the positive electron-hole exchange interaction constant on the binding energy of neutral donor bound excitons in AlN (2021)
  • Author(s): R. Ishii, A. Yoshikawa, H. Kobayashi, M. Funato, and Y. Kawakami
  • Journal Title: Japanese Journal of Applied Physics Volume: 60 Issue: 8 Pages: 080901-080901
  • DOI: 10.35848/1347-4065/ac15ae
  • Peer Reviewed
• [Journal Article] Influence of substrate misorientation on the emission and waveguiding properties of a blue (In,Al,Ga)N laser-like structure studied by synchrotron radiation microbeam X-ray diffraction (2021)
  • Author(s): A. Kafar, A. Sakaki, R. Ishii, S. Stanczyk, K. Gibasiewicz, Y. Matsuda, D. Schiavon, S. Grzanka, T. Suski, P. Perlin, M. Funato, and Y. Kawakami
  • Journal Title: Photonics Research Volume: 9 Issue: 3 Pages: 299-307
  • DOI: 10.1364/prj.411701
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Bias-dependent time-resolved photoluminescence spectroscopy on 265-nm AlGaN-based LEDs on AlN substrates (2021)
  • Author(s): R. Ishii, A. Yoshikawa, K. Nagase, M. Funato, and Y. Kawakami
  • Journal Title: Japanese Journal of Applied Physics Volume: 60 Issue: 2 Pages: 020903-020903
  • DOI: 10.35848/1347-4065/abd91d
  • Peer Reviewed
• [Journal Article] Radiative recombination efficiency of AlGaN quantum wells: do we estimate it accurately in a proper way? (2020)
  • Author(s): Y. Kawakami, M. Funato, and R. Ishii
  • Journal Title: J. Phys. D: Appl. Phys. Volume: 53 Issue: 50 Pages: 503001-503001
  • DOI: 10.1088/1361-6463/aba64c
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] 265 nm AlGaN-based deep-ultraviolet light-emitting diodes grown on AlN substrates studied by photoluminescence spectroscopy under ideal pulsed selective and non-selective excitation conditions (2020)
  • Author(s): R. Ishii, A. Yoshikawa, K. Nagase, M. Funato, and Y. Kawakami
  • Journal Title: Applied Physics Express Volume: 13 Issue: 10 Pages: 102005-102005
  • DOI: 10.35848/1882-0786/abb86f
  • Peer Reviewed
• [Journal Article] Above 25 nm emission wavelength shift in blue-violet InGaN quantum wells induced by GaN substrate misorientation profiling: towards broad-band superluminescent diodes (2020)
  • Author(s): A. Kafar, R. Ishii, K. Gibasiewicz, Y. Matsuda, S. Stanczyk, D. Schiavon, S. Grzanka, M. Tano, A. Sakaki, T. Suski, P. Perlin, M. Funato, and Y. Kawakami
  • Journal Title: Optics Express Volume: 28 Issue: 15 Pages: 22524-22539
  • DOI: 10.1364/oe.394580
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Long-range electron-hole exchange interaction in aluminum nitride (2020)
  • Author(s): R. Ishii, M. Funato, and Y. Kawakami
  • Journal Title: Physical Review B Volume: 102 Issue: 15 Pages: 1-5
  • DOI: 10.1103/physrevb.102.155202
  • Peer Reviewed
• [Journal Article] エレクトロルミネッセンス・フォトルミネッセンス法によるAlN基板上265nm帯AlGaN LEDの評価 (2020)
  • Author(s): 石井良太・吉川 陽・永瀬和宏・船戸 充・川上養一
  • Journal Title: 信学技報 Volume: 120 Pages: 21-24
• [Journal Article] Temperature-dependent electroluminescence study on 265-nm AlGaN-based deep-ultraviolet light-emitting diodes grown on AlN substrates (2020)
  • Author(s): R. Ishii, A. Yoshikawa, K. Nagase, M. Funato, and Y. Kawakami
  • Journal Title: AIP Advances Volume: 10 Issue: 12 Pages: 125014-125014
  • DOI: 10.1063/5.0024179
  • Peer Reviewed / Open Access
• [Journal Article] Direct detection of rare earth ion distributions in gallium nitride and its influence on growth morphology (2020)
  • Author(s): B. Mitchell, D. Timmerman, W. Zhu, J. Y. Lin, H. X. Jiang, J. Poplawsky, R. Ishii, Y. Kawakami, V. Dierolf, J. Tatebayashi, S. Ichikawa, and Y. Fujiwara
  • Journal Title: Journal of Applied Physics Volume: 127 Issue: 1 Pages: 013102-013102
  • DOI: 10.1063/1.5134050
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Achromatic Deep Ultraviolet Lens Using Novel Optical Materials (2020)
  • Author(s): Y. Minami, M. Cadatal-Raduban, K. Kuroda, K. Shinohara, Y. Lai, K. Yamanoi, N. Sarukura, T. Shimizu, R. Ishii, Y. Kawakami, N. Kabasawa, T. Amano, K. Kiyohara, and M. Kiyohara
  • Journal Title: physica status solidi (b) Volume: in press Issue: 8 Pages: 1900480-1900480
  • DOI: 10.1002/pssb.201900480
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Pushing the limits of deep-ultraviolet scanning near-field optical microscopy (2019)
  • Author(s): R. Ishii, M. Funato and Y. Kawakami
  • Journal Title: APL Photonics Volume: 4 Issue: 7 Pages: 070801-070801
  • DOI: 10.1063/1.5097865
  • Peer Reviewed / Open Access
• [Journal Article] Intrinsic exciton transitions of isotopically purified 13C studied by photoluminescence and transmission spectroscopy (2019)
  • Author(s): Ishii Ryota、Shikata Shinichi、Teraji Tokuyuki、Kanda Hisao、Watanabe Hideyuki、Funato Mitsuru、Kawakami Yoichi
  • Journal Title: Japanese Journal of Applied Physics Volume: 59 Issue: 1 Pages: 010903-010903
  • DOI: 10.7567/1347-4065/ab5b77
  • NAID: 210000157647
  • Peer Reviewed
• [Journal Article] Synthesis of nano-polycrystalline diamond from glassy carbon at pressures up to 25 GPa (2019)
  • Author(s): Irifune, T., Ueda, C., Ohshita, S., Ohfuji, H., Kunimoto, T. and Shinmei, T.
  • Journal Title: High Pressure Research Volume: 40 Issue: 1 Pages: 96-106
  • DOI: 10.1080/08957959.2019.1702658
  • Peer Reviewed
• [Journal Article] Impact of face-to-face annealed sputtered AlN on the optical properties of AlGaN multiple quantum wells (2019)
  • Author(s): K. Shojiki, R. Ishii, K. Uesugi, M. Funato, Y. Kawakami, H. Miyake
  • Journal Title: AIP Advances Volume: 9 Issue: 12 Pages: 125342-125342
  • DOI: 10.1063/1.5125799
  • Peer Reviewed / Open Access
• [Presentation] Temperature-dependent electroluminescence spectroscopy on 265-nm AlGaN-based LEDs grown on AlN substrates (2022)
  • Author(s): Ryota Ishii, Akira Yoshikawa, Mitsuru Funato, and Yoichi Kawakami
  • Organizer: IWSingularity 2022
  • Int'l Joint Research / Invited
• [Presentation] Luminescence spectroscopies on 265-nm AlGaN DUV LEDs and AlN films grown on AlN substrates (2022)
  • Author(s): Ryota Ishii, Mitsuru Funato, and Yoichi Kawakami
  • Organizer: SPIE PHOTONICS WEST 2022
  • Int'l Joint Research / Invited
• [Presentation] Si添加ホモエピタキシャルAlN薄膜の極低温下フォトルミネッセンス測定 (2021)
  • Author(s): 石井良太，船戸充，川上養一，吉川陽，小林敬嗣
  • Organizer: 第82回応用物理学会秋季学術講演会
• [Presentation] Epitaxially laterally overgrown AlGaN quantum wells studied by selectively and non-selectively excited photoluminescence (2021)
  • Author(s): Shiki Tanaka, Ryota Ishii, Norman Susilo, Tim Wernicke, Michael Kneissl, Mitsuru Funato, and Yoichi Kawakami
  • Organizer: 第82回応用物理学会秋季学術講演会
• [Presentation] Recent progress in deep-ultraviolet scanning near-field optical microscope: a tool visualizing the luminescence properties of Al-rich AlGaN active layers (2021)
  • Author(s): Ryota Ishii, Mitsuru Funato, and Yoichi Kawakami
  • Organizer: SPIE PHOTONICS WEST (Online, Mar. 6-11, 2021),
  • Int'l Joint Research / Invited
• [Presentation] Recombination Mechanism in III-Nitride Based Singularity Structures by Scanning Near-field Optical Microscopy (2021)
  • Author(s): Yoichi Kawakami, Ryota Ishii, and Mitsuru Funato
  • Organizer: The 8th Asian Conference on Crystal Growth and Crystal Technology
  • Int'l Joint Research
• [Presentation] エレクトロルミネッセンス・フォトルミネッセンス法によるAlN基板上265 nm帯AlGaN LEDの評価 (2020)
  • Author(s): 石井良太・吉川 陽・永瀬和宏・船戸 充・川上養一
  • Organizer: LQE CPM ED
• [Presentation] Exciton fine structure of aluminum nitride (2020)
  • Author(s): R. Ishii, M. Funato and Y. Kawakami
  • Organizer: SPIE Photonics West, San Francisco, USA, 2020 (1-6 Feb., 2020) (invited)
  • Int'l Joint Research / Invited
• [Presentation] Comparative study of AlGaN multiple quantum wells on annealed-sputtered-AlN and MOVPE-grown-AlN on sapphire substrates (2019)
  • Author(s): K. Shojiki, R. Ishii, K. Uesugi, M. Funato, Y. Kawakami and H. Miyake
  • Organizer: 13th International Conference on Nitride Semiconductors, Washington, USA (July 7-12, 2019)
  • Int'l Joint Research
• [Presentation] Engineering of emission wavelength of InGaN quantum wells by fabrication of spatial off-cut variation (2019)
  • Author(s): A. Kafar, R. Ishii, S. Stanczyk, K. Gibasiewicz, S. Grzanka, T. Suski, P. Perlin, M. Funato and Y. Kawakami
  • Organizer: 9th Asia-Pacific Workshop on Widegap Semiconductors, Okinawa, Japan (Nov. 10-15, 2019)
  • Int'l Joint Research
• [Presentation] High-temperature promoted nonradiative recombination at threading dislocations in blue-emitting InGaN quantum well (2019)
  • Author(s): R. Ishii, Y. Koyama, M. Funato, and Y. Kawakami
  • Organizer: 9th Asia-Pacific Workshop on Widegap Semiconductors, Okinawa, Japan (Nov. 10-15, 2019)
  • Int'l Joint Research
• [Presentation] アニール処理スパッタAlN膜上AlGaN多重量子井戸構造の光学特性 (2019)
  • Author(s): 正直花奈子, 石井良太, 上杉謙次郎, 船戸充, 川上養一, 三宅秀人
  • Organizer: 第11回ナノ構造・エピタキシャル成長講演会, 広島大学
• [Presentation] 青色・緑色発光InGaN量子井戸構造の高温環境下における顕微PLマッピング (2019)
  • Author(s): 石井良太, 小山友二, 船戸充, 川上養一
  • Organizer: 第80回応用物理学会秋季学術講演会, 北海道大学
• [Presentation] Study of luminescence properties of InGaN layers with wide-range lateral indium content profiling (2019)
  • Author(s): A. Kafar, R. Ishii, S .Stanczyk, K. Gibasiewicz, S. Grzanka, T. Suski, P. Perlin, M. Funato and Y. Kawakami
  • Organizer: 第80回応用物理学会秋季学術講演会, 北海道大学
• [Remarks] 川上研究室
  • URL: http://www.optomater.kuee.kyoto-u.ac.jp/
• [Patent(Industrial Property Rights)] 発振器、増幅器 (2022)
  • Inventor(s): 石井 良太, 外5名
  • Industrial Property Rights Holder: 国立大学法人京都大学、株式会社トクヤマ
  • Industrial Property Rights Type: 特許
  • Industrial Property Number: 2022-065458
  • Filing Date: 2022