无铯激活负电子亲和势AlGaN日盲紫外光电子发射材料的MOCVD生长与光电特性研究

负电子亲和势AlGaN日盲紫外光电子发射材料是能够满足国防建设与国民经济建设应用需求，实现高增益、本征截止日盲紫外光电探测的核心基础材料。本项目针对高活性铯激活负电子亲和势光阴极易于受到污染并失效的问题，提出开展无铯激活负电子亲和势AlGaN光电子发射材料的MOCVD生长与性能研究。重点解决利用AlGaN材料自发极化诱导表面能带弯曲获得负电子亲和势中的科学问题与实现途径。并通过开展高质量氮极性AlGaN材料的MOCVD生长研究；表面能带结构与能带调控的理论与实验研究；高载流子浓度p-型掺杂与掺杂调控研究；光电子激发与光电子发射动力学过程研究；以及AlGaN材料光电性能研究等，揭示无铯激活AlGaN光电子发射材料负电子亲和势形成机制和光电子发射规律。为获得高稳定性、实用化无铯激活负电子亲和势AlGaN日盲紫外光阴极奠定理论和实验基础。

Negative electron affinity (NEA)AlGaN photoemissive materials are the most important fundamental materials for solar-blind ultraviolet detectors with high gain and intrinsic cutoff spectra response. These devices are widely used in military and civil field. Conventional GaN based photocathodes are cesiation to achive NEA and the photocathodes suffer from chemical instability and degradation with time. In this project, Ce-free NEA AlGaN photoemission materials will be grown by MOCVD and the optoelectronics properties will be investigated. It is proposed that by existence of spontaneous polarization in N-polar AlGaN, the conduction band will be pulled close to the Fermi level of p-AlGaN and the NEA will be formed. In detail of this project, the high quality N-polar AlGaN will be grown by MOCVD. The energy band structures of AlGaN surface will be investigated theoretically and experimentally. The method of high Mg doping p type AlGaN with high Al composition and carrier concentration distribution modification will be found. It also will be investigated that the dynamic processes of photocarrier excitation, photoemission and the optoelectronics properties of the Cs-free NEA AlGaN materials. The aims of this project are to reveal the rule of how to get NEA AlGaN without cesiation and lay the fundations for obtain the stable and long-life Cs-free NEA AlGaN photocathoed.