采用分子束外延技术制备了具有相同的均匀掺杂或指数掺杂的反射式(r-mode)和透射式(t-mode)GaAs光电阴极样品。利用在线光谱响应测试系统测试了它们的光谱响应，并对实验曲线进行拟合，得到了电子扩散长度和积分灵敏度。结果表明，经工艺处理后的t-mode样品，在均匀掺杂情况下其电子扩散长度的减小量是指数掺杂情况的两倍，积分灵敏度的降低量后者比前者少3%，因此指数掺杂方式有利于降低组件制备工艺对阴极材料发射层的影响。

By molecular beam epitaxy technology, reflection-mode (r-mode) and transmission-mode (t-mode) GaAs photocathode samples with identical uniform doping or exponential doping are prepared. Their spectral response are measured based on the on-line spectral response measuring system and via fitting to the experimental curves, the electron diffusion length and integral sensitivity are obtained. These results indicate that, after the cathode module processing of the t-mode sample, the decrease of the electron diffusion length for sample with uniform doping is twice that for sample with exponential doping, the reduction of the integral sensitivity for the latter is smaller by 3% than that for the former. The exponential doping way is beneficial to reducing the influence of cathode module process on photoemission layer of photocathode materials.