通过建立原子结构的理论模型和电离杂质散射理论公式,研究了光电子在透射式均匀掺杂GaAs光电阴极体内的输运过程,分析了光电阴极的掺杂浓度、发射层厚度、电子扩散长度等相关因素对阴极出射面的弥散圆斑以及到达阴极出射面的光电子数与激发光电子总数之比的影响.计算结果表明,当透射式均匀掺杂GaAs光电阴极发射层厚度为2μm、电子扩散长度为3.6μm、掺杂浓度为1×1019cm-3时,其极限线分辨率为769mm-1.此GaAs材料光电子的输运性能研究,对制备高性能GaAs光电阴极和提高微光像增强器的分辨率有重要的参考价值.
The transport of photoelectrons in a uniform-doping transmission-mode GaAs photocathode is calculated by establishing the models of atomic configuration and ionized impurity scattering.And the influence of the doping concentration of photocathode,the photocathode thickness,the electron diffusion length on the diffused circle and the ratio of the number of photoelectrons reaching the emit-surface to the number of exited photoelectrons at the back-interface of GaAs photocathode are analyzed.The calculated results show that the limiting linear resolution is 769 mm-1 with the cathode thickness being 2μm,the electron diffusion length 3.6μm and the uniform-doping concentration 1×1019 cm-3.The research on the transport of photoelectrons is worthwhile for preparing the high-performance GaAs cathode and improving the resolution of intensifier image.