负电子亲和势GaN光电阴极特性研究

STUDY ON CHARACTERISTICS OF NEGATIVE ELECTRON AFFINITY GAN PHOTOCATHODE

分析了NEA GaN光电阴极的产生背景,介绍了NEA GaN光电阴极的结构以及工作模式,研究了GaN光电阴极的光电发射机理以及NEA特性的形成原因,p型GaN经过Cs、O处理后的有效电子亲和势约为-1.2eV。分析表明:充分激活后形成的双偶极层是表面真空能级降低的原因,体内产生的光电子按照光电发射的"三步模型"逸出到真空中。

The appearance background of NEA GaN photocathode was analysed, the structure and operation mode of NEA GaN photocathode were discussed. The photoemission mechanism and the formation cause of NEA property for GaN photocathode were studied. The effective electron affinity for p-GaN is about -1.2 eV after being processed with Cs and O. The analysis shows ： the reason of the reduction of vacuum energy level is the formation of the double dipole layer after being fully activated successfully. The photoelectrons from the bulk will escape to the vacuum according to photoemission ＂3-step model＂ theory.