GaAs光电阴极激活后的表面势垒评估研究

摘要

According to the ratios of the peak-values of photocurrents arising separately during the single Cs activation and during the Cs-O activation for negative electron affinity(NEA) GaAs photocathode, and the theoretical energy distributions of the photoelectrons passing separately through the single and the double potential barriers, a new method of evaluating the surface potential barrier parameters of NEA GaAs photoeathode is presented. The results obtained by this method accord well with the double-dipole model theory and are in agreement with the results by fitting the experimental electrons energy distribution curve. The method is simple and efficave, which enriches the approaches to the evaluation of activation effect and surface characteristic of NEA GaAs photocathodes without increasing other test means.%根据阴极制备过程中单独Cs激活和Cs-O交替激活两个阶段产生的光电流的峰值比,结合对电子穿过表面单势垒和双势垒后能量分布的理论曲线,提出了一种评估NEA GaAs光阴极表面势垒参数的新方法.利用该方法研究的结果完全符合双偶极层模型理论,并且和对实测阴极电子能量分布曲线拟合的结果非常一致.该方法简单、有效.在不增加测试手段的前提下,丰富了对NEA GaAs光电阴极激活效果及表面特征评价的方法和途径.