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2018 年度 実施状況報告書

Searching new operation area for QCL by Gain Mapping using NEGF

研究課題

研究課題/領域番号 18K04251
研究機関国立研究開発法人理化学研究所

研究代表者

Yun Joosun  国立研究開発法人理化学研究所, 開拓研究本部, 基礎科学特別研究員 (30817359)

研究分担者 平山 秀樹  国立研究開発法人理化学研究所, 開拓研究本部, 主任研究員 (70270593)
研究期間 (年度) 2018-04-01 – 2021-03-31
キーワードNEGF / QCL / GaN / AlGaN / GaAs / AlGaAs
研究実績の概要

We found that the polarization-related carrier scattering processes such as dipole scattering, polarization Coulomb field scattering and polarization surface roughness scattering should be considered for the correct design and simulation of GaN/AlGaN QCL structures. Therefore, our proposed structures must be upgraded by including spectral broadening originated from these polarization-related scattering. Since the commercial software supports only traditional scattering mechanisms such as polar optical phonon (POP), acoustic phonon, interface roughness, electron-electron scattering and impurity scattering, we accelerated to develop our own NEGF simulator in order to progress our project to the right direction. We adopted the calculation algorithm of Appl. Phys. Rev. 1, 011307 (2014) into the new simulator. After finishing the development, the software was moved to the supercomputer system in RIKEN (HOKUSAI BigWaterfall) after hybrid parallelization based on OpenMP and MPI (Message Passing Interface). The validity of this new simulator was secured by comparing with several previously published experimental reports for GaAs/AlGaAs QCLs. Also, gain-mapping was performed for these structures by utilizing the new developed software as a test process. After that, we have been designing self-energies for dipole scattering in AlGaN material system as a first. We expect that the improved and more reasonable design for GaN-based QCLs will be available soon. Also, the influence of polarization-related scattering processes in quantum transport of GaN/AlGaN QCLs may be unveiled.

現在までの達成度 (区分)
現在までの達成度 (区分)

3: やや遅れている

理由

Our plan was slightly delayed after we find the importance of polarization-related scattering mechanisms in GaN/AlGaN devices. After we were noticed to those, we accelerated to develop NEGF software by ourselves since the Nextnano's commercial software does not support polarization-related scattering mechanisms currently. Since the self-energy models for these scattering processes in GaN/AlGaN have not been reported yet, we have been developing new self-energy models by ourselves. We expect several fruitful achievements from this year.

今後の研究の推進方策

Future plan is like follow.
1. Design of self-energies for dipole scattering and polarization surface roughness scattering.
2. Structural design and gain-mapping of several GaN-based QCL structures in order to find new operational frequency and temperature range
4. Growth and fabrication of designed structures
5. Measurement of fabricated QCL devices

備考

We have developed a quantum transport simulator adopting non-equilibrium Green's function based on real space representation. Its development was finished recently and moved to a supercomputer.

  • 研究成果

    (3件)

すべて 2018 その他

すべて 雑誌論文 (1件) (うち国際共著 1件、 査読あり 1件) 学会発表 (1件) (うち国際学会 1件) 備考 (1件)

  • [雑誌論文] Broadening mechanisms and self-consistent gain calculations for GaN quantum cascade laser structures2018

    • 著者名/発表者名
      Wang Ke、Grange Thomas、Lin Tsung-Tse、Wang Li、Jehn Zoltan、Birner Stefan、Yun Joosun、Terashima Wataru、Hirayama Hideki
    • 雑誌名

      Applied Physics Letters

      巻: 113 ページ: 061109~061109

    • DOI

      10.1063/1.5029520

    • 査読あり / 国際共著
  • [学会発表] Broadening mechanisms and self-consistent gain calculations for GaN quantum cascade laser structures2018

    • 著者名/発表者名
      Ke Wang, Tsung-Tse Lin, Li Wang, Joosun Yun, Wataru Terashima, Hideki Hirayama, Thomas Grange, Zoltan Jehn, and Stefan Birner
    • 学会等名
      International Workshop on Nitride Semiconductors (IWN) 2018
    • 国際学会
  • [備考] Design of high performance THz-QCL and DUV-LED

    • URL

      http://i.riken.jp/download/Q18381.pdf

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公開日: 2019-12-27  

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