Development of Novel Electron Emitter for Photon Enhanced Thermionic Emission Using Thin Film Semiconductor Material

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04934
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 29020:Thin film/surface and interfacial physical properties-related
• Research Institution: Shizuoka University
• Principal Investigator: Akihisa Ogino 静岡大学, 工学部, 准教授 (90377721)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 熱電子放出 / 二硫化モリブデン / 窒化アルミニウムガリウム

Outline of Final Research Achievements

For the purpose of development of novel electron emitter for photon enhanced thermionic emission using thin film semiconductor material, molybdenum disulfide (MoS2) thin film was synthesized by CVD method and enhanced by plasma treatment. MoS2 was n-typed by forming sulfur defects by argon or hydrogen plasma treatment, and p-typed by injecting nitrogen into the sulfur defects by nitrogen plasma treatment.
The thermionic emission of Si-doped aluminum gallium nitride (AlGaN) films with Cs adoption was investigated. Threshold temperatures of thermionic emission was around 300 ℃ and it is considerably lower than the temperatures of conventional thermionic energy converter. The work function decreases as the AlN mole fraction x in the AlGaN samples is increased. According to the output characteristics of thermionic converter with AlGaN emitter, the output voltage was 0.14 V at the emitter temperature 600 ℃.

Free Research Field

プラズマ応用

Academic Significance and Societal Importance of the Research Achievements

低温で高効率な熱電子発電の実現に向けて、二硫化モリブデンおよび窒化アルミニウムガリウム半導体による低温熱電子放出源を開発し、従来の金属熱電子源よりも圧倒的に低い300℃での熱電子放出を観測した。二硫化モリブデンの硫黄欠陥形成とドーピングにおいて、低温プラズマ処理は有効である。プラズマ処理技術を用いて二硫化モリブデンのバンド構造ならびに表面特性を向上させることで、可視光を効率的に電子放出に利用できる電子減が期待できる。本研究の成果は、半導体エミッタの低抵抗化、低電子親和力化について有用であり、狭真空ギャップの熱電発電器モジュールの作製において有用な知見といえる。