红外技术2017，Vol.39Issue(12)：1073-1077,5.
NEA GaN和GaAs光电阴极的比较
Comparison of NEA GaN and GaAs Photocathodes
摘要
Abstract
In view of the increase in photocurrent in the alternation of Cs-O in the activation process of GaN-based photocathode, in this paper, the properties of GaN and GaAs materials, the surface structure, and the photocurrent of the photocathode during the activation process are compared. It is found that the melting point of GaN is higher than that of GaAs, and a higher thermal cleaning temperature is necessary in the preparation of GaN-based photocathode. Using the double dipole model to describe the photoelectric emission mechanism of the GaN(1000) and GaAs(100) surface, the GaN(1000) surface Cs atoms and O atoms form the second dipole moment of O-Cs that is almost flat on the surface and contribute little to the photoelectric emission; the GaAs(100) surface Cs atoms and O atoms form the second dipole moment of O-Cs that is almost vertical to the surface, reducing the surface work function of the photoelectric emission contribution. In the Cs-O activation, the photocurrent formed by the alternating process of Cs and O for the GaAs photocathode could be several times even more than 100 times higher than that of pure Cs activation, whereas the GaN photocathode only increases by~20%. By first principle calculations, compared to the GaN(1000) surface ratio, GaN base(1120) and (1010) are the photoelectric emission potential surface; and the sphalerite GaN base(100) surface is expected to achieve better results.关键词
GaN光电阴极/GaAs光电阴极/表面结构/光电流/偶极矩Key words
GaN photocathode/GaAs photocathode/surface structure/photocurrent/dipole moment分类
信息技术与安全科学引用本文复制引用
常本康..NEA GaN和GaAs光电阴极的比较[J].红外技术,2017,39(12):1073-1077,5.基金项目
国家自然科学基金重大研究计划(91433108). （91433108）
