Study on high efficiency AlGaN UVC-LED with oxide semiconductor tunelling junction

• Project/Area Number: 18K04226
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: The University of Electro-Communications
• Principal Investigator: uchida kazuo 電気通信大学, 大学院情報理工学研究科, 教授 (80293116)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2019: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000); Fiscal Year 2018: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
• Keywords: UV-LED / 窒化物半導体 / 酸化物半導体 / 有機金属気相成長法 / RFスパッタリング / トンネル接合 / AlGaN / ZnO / UVLED / MOVPE / UV LED / AlGaN系UVC-LED / 酸化物半導体トンネル電極

Outline of Final Research Achievements

The AlGaN UV-LED with n-ZnO tunneling layer was fabricated and its UV emission was successfully observed by electroluminescence. The tunneling resistance was identified in Its I-V characteristics. A superior emission in optical intensity to conventional LEDs was also observed in low current regime. This can be attributed to enhanced hole injections by tunneling. Further, the theoretical calculation of the energy band structure of p-AlGaN/n-ZnO tunnel junction revealed that the electric field enhanced by negatively polarized charges localized at the junction could improve injection efficiency of holes into p-AlGaN.

Academic Significance and Societal Importance of the Research Achievements

本研究では窒化物半導体と酸化物半導体のハイブリッド化による新規高機能デバイスとしてのn-ZnOトンネル層を有するAlGaN UV-LEDの作成プロセス開発と物性の探索を行い、新たな学術的知見が得られた。また研究結果は、現在、世界規模で蔓延するコロナウイルスを不活化できる深紫外LEDの問題点である、高抵抗、低効率の改善に寄与することを明示しており、社会的意義は高い。

Research Products

• [Presentation] 正孔注入促進に向けたp-AlGaN/n-ZnOトンネル接合のバンド構造解析 (2021)
  • Author(s): 浮田 駿、田尻 武義、内田 和男
  • Organizer: 第68回応用物理学会春季学術講演会
• [Presentation] p型コンタクト層にn-ZnO層を接合したAlGaN系pnダイオードのEL特性評価 (2021)
  • Author(s): 孫 錚、王 新磊、森元 諄、田尻 武義、内田 和男
  • Organizer: 第68回応用物理学会春季学術講演会
• [Presentation] p型コンタクト層にn-ZnOトンネル層を有するAlGaN系pnダイオードの作製及び電気的評価 (2020)
  • Author(s): 孫 錚，森元 諄, 大黒 将也,田尻 武義, 内田 和男
  • Organizer: 第81回応用物理学会秋季学術講演会
• [Presentation] High-Al content AlGaN pn diode with p-AlGaN improved by the UV wet oxidation (2018)
  • Author(s): Xiaojia Zhang, Jun Morimoto, Kazuo Uchida, and Shinji Nozaki
  • Organizer: 19th International Conference on Metalorganic Vapor Phase Epitaxy
  • Int'l Joint Research