氮化镓光阴极薄膜材料表面光电压谱特性

在蓝宝石基底上外延生长了多层结构氮化镓光阴极薄膜材料并进行表面光电压测试；对比分析了掺杂类型、厚度和掺杂方式对氮化镓材料表面光电压的影响，确定了多层结构氮化镓材料表面光电压产生机理；借助亚带隙激光辅助，针对均匀掺杂和δ-掺杂氮化镓(GaN)光电阴极薄膜材料进行了表面光电压测试；实验数据表明，相较于均匀掺杂，δ-掺杂可以获得更好生长质量，但也提高了在能级(E_v+0.65)eV～(E_v+1.07)eV范围的缺陷态密度。

Characteristics of Photovoltage Spectrum on Surfaces of Gallium Nitride Photocathode Film Materials

In this study, we epitaxially grew a multilayer structure of gallium nitride (GaN) photocathode film material on a sapphire substrate and conducted a surface photovoltage test. The effects of doping type, thickness, and doping method on the surface photovoltage of the gallium nitride material were compared and analyzed, and the mechanism of surface photovoltage generation of the multi-layered gallium nitride material was determined. A surface photovoltage test was performed on uniformly doped and delta-doped gallium nitride photocathode thin film materials using sub-band-gap laser. Experimental data shows that better growth quality was achieved using δ-doping than that achieved using uniform doping; however, δ-doping increased the density of defect states in the (E_v+0.65)–(E_v+1.07) eV energy levels.