变掺杂GaN光电阴极是指在光电发射层内，通过采用体内掺杂浓度高，往表面浓度逐渐降低的变掺杂方法，构建从内到外的内建电场，提高阴极量子效率。本项目将运用实验和理论相结合的方法，开展变掺杂NEA GaN光电阴极材料特性与量子效率理论研究。本项目通过电子从变掺杂NEA GaN光电阴极体内到表面的输运特性，研究变掺杂阴极材料的能带结构和内建电场；探索变掺杂NEA GaN光电阴极量子效率理论；利用量子效率理论设计最佳变掺杂GaN光电阴极结构；通过测试材料表面光电压谱等方法，完善变掺杂材料性能表征手段，研究阴极材料表面光伏特性和表面层结构；进行变掺杂阴极材料的制备实验，并和理论结果进行对比分析，通过不断优化材料设计，使制备的阴极量子效率达到50%以上。本课题对开展高性能变掺杂GaN光电阴极研究，推动我国紫外探测、高能物理、微电子学和电子束平版印刷技术等领域的发展，具有重要的理论意义和应用价值。

For variable doping GaN photocathode, the quantum efficiency can be increased by adopting the variable doping method. That is to say, in the photoemission layer, the bulk doping concentration is high, and doping concentration is decreased gradually from bulk to surface, thus the built-in field is built. By the means of combining experiment and theory, the research of material characteristics and quantum efficiency theory for variable doping NEA GaN photocathode material will be carried out. By the electron transportation characteristic from bulk to surface of variable doping GaN photocathode, the energy band structure and the built-in field for variable doping GaN photocathode will be studied. The quantum efficiency theory of variable doping NEA GaN photocathode will be probed into. And the best structure of variable doping GaN photocathode will be designed with the quantum efficiency theory. By the means of testing the surface photovoltage spectroscopy etc., the performance evaluation means can be completed, the photovoltaic characteristics and the surface layer structure will be studied. The preparation experiments for variable doping GaN photocathode will be carried out. And the comparative analysis will be completed with the theory results. By optimizing the material design continuously, the quantum efficiency of GaN photocathode will be more than 50%.This project has important theory significance and application value to develop the theory research on variable doping GaN photocathode and promote the development of UV detection, high energy physics, microelectronics and electron beam lithography etc..