Deng Wenjuan, Zou Jijun, Peng Xincun, Feng Lin, Zhu Zhifu, Wang Weilu, Zhang Yijun, Chang Benkang
Appl Opt. 2015 Feb 20;54(6):1414-9. doi: 10.1364/AO.54.001414.
The resolution model of a graded doping and graded composition transmission-mode AlGaAs/GaAs photocathode is solved numerically from the two-dimensional continuity equations. According to the model, we calculate the theoretical modulation transfer function (MTF) of different graded doping and graded composition structures. The simulation results show that both graded composition and graded doping structures can increase the resolution of the photocathode. The exponentially doping and linear composition photocathode has the maximum resolution among the possible graded doping and graded composition photocathodes. The resolution improvement is attributed to the built-in electric field induced by a graded composition or graded doping structure. The simulation results also show that the MTFs of AlGaAs/GaAs cathodes increase as the AlGaAs layer thickness decreases, or the incident light wavelength increases.
从二维连续性方程对渐变掺杂和渐变组分传输模式的AlGaAs/GaAs光电阴极的分辨率模型进行了数值求解。根据该模型，我们计算了不同渐变掺杂和渐变组分结构的理论调制传递函数（MTF）。模拟结果表明，渐变组分和渐变掺杂结构均能提高光电阴极的分辨率。在可能的渐变掺杂和渐变组分光电阴极中，指数掺杂和线性组分的光电阴极具有最高分辨率。分辨率的提高归因于渐变组分或渐变掺杂结构所诱导的内建电场。模拟结果还表明，AlGaAs/GaAs阴极的MTF随着AlGaAs层厚度的减小或入射光波长的增加而增大。
