NEA光电阴极的(Cs,O)激活工艺研究

在自行研制的负电子亲和势光电阴极性能评估实验系统上,首次利用动态光谱响应技术和变角X射线光电子能谱(XPS)表面分析技术研究了GaAs光电阴极的(Cs,O)激活工艺.获得了首次导Cs、(Cs,O)导入以及(Cs,O)循环的优化激活条件.XPS分析给出GaAs(Cs,O)的最佳激活层厚度为0.82 nm,首次导Cs达到峰值光电发射时的Cs覆盖率为0.71个单层.在优化激活条件下,可以在国产反射式GaAs上获得1025 μA/lm的积分灵敏度.

(Cs,O) Activation Technique for NEA Photocathode

On basis of self-developing experimental system for evaluating NEA photocathodes properties, on-line spectral response measurement technology and angular-dependent X-ray photoelectron spectroscopy(XPS)technology are firstly used to research the(Cs,O)activation technique of GaAs NEA photocathodes. A detailed analysis of first addition of Cs, optimum(Cs,O)deposition and alternation activation are made. The optimum thickness of activation layer is 0.82 nm for successfully activated GaAs NEA photocathode,and the photoemission peaks at 0.71 monolayer of Cs coverage. The results show that the photosensitivity for GaAs photocathode activated with substrate made in China can achieve 1025 μA/lm.