半导体纳米线阵列具备半导体薄膜材料所不具有的光子吸收充分、光反射小、光电子输运到材料表面的距离短等特性，这些特性非常有利于光电发射。本项目拟利用上述特性，开展GaAs纳米线阵列光阴极制备及其理论研究，通过MOCVD外延生长和金属辅助化学刻蚀法制备GaAs纳米线阵列材料，表征分析其光子吸收与电子输运特性，构建纳米线光阴极能带结构模型；基于纳米线阵列光电特性以及能带结构模型的研究，建立GaAs纳米线阵列光阴极光电发射理论模型；在超高真空激活系统中制备GaAs纳米线阵列光阴极，利用原位表征分析技术，建立GaAs纳米线NEA表面模型；测试不同光照角度下的阴极光谱响应曲线，利用光电发射理论进行仿真分析，揭示GaAs纳米线阵列光阴极光电发射机理，优化阴极制备工艺，得到高性能GaAs纳米线阵列光阴极。GaAs纳米线阵列光阴极在太阳能、微光夜视、光电探测、电子源等领域具有很好的应用前景。

Semiconductor nanowire arrays have already been shown to have a high absorption coefficient or excellent light trapping, low reflective loss and a short distance that electrons need to travel along nanowire diameter to the wire surface compared to semiconductor thin film. These properties are very useful for photoemission. In this project, we will investigate the preparation and photoemission theory of GaAs wire-array photocathodes. GaAs nanowire arrays will be grown by metal-organic chemical vapor deposiyion (MOCVD) and be synthesized using metal-assisted chemical etching (MacEtch). The photon absorption properties and electron transport properties of nanowire arrays will be characterized and the band structure of nanowires will be constructed. Based on these optoelectric properties and band structure of the nanowire arrays, we will establish a photoemission theory model for GaAs wire-array photocathode. GaAs wire-array photocathodes will be prepared in an ultra-high vacuum activation chamber. Based on the application of in-Situ characterization techniques to the study of nanowire photocathode surface, we will construct a NEA surface model for GaAs nanowire photocathodes. The spectral response of the nanowire photocathodes will be measured using spectral response measuring instrument and analyzed using photoemission theory. Based on these expermental and theoretical results, we will reveal the photoemission mechanism and optimize the preparation methods of nanowire photocathodes, and achieve a high performance GaAs wire-array photocathode. GaAs wire-array photocathodes have great potential for applications in solar energy, low-light level night vision, photoeletric detection, electron source etc.