n-InP/p-InP/p-InGaAs场助光电阴极理论建模与仿真  

Theoretical Modeling and Simulation of n-InP/p-InP/p-InGaAs Field-Assisted Photocathode

作　　者：岳江楠 李禹晴 陈鑫龙[2] 徐鹏霄[2] 邓文娟[1] 彭新村[1] 邹继军[1] YUE Jiangnan;LI Yuqing;CHEN Xinlong;XU Pengxiao;DENG Wenjuan;PENG Xincun;ZOU Jijun(East China University of Technology Engineering Research Center of Nuclear Technology Application,Nanchang 330013,China;The 55th Research Institute of China Electronics Technology Corporation,Nanjing 210000,China)

机构地区：[1]东华理工大学核技术应用教育部工程研究中心,南昌330013 [2]中国电子科技集团公司第五十五研究所,南京210000

出　　处：《真空科学与技术学报》2023年第6期547-553,共7页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(11875012,61961001,62061001);江西省自然科学基金项目(20192ACBL20003,20181BAB202026,20202BAB202013);江西省“双千计划”项目(jxsq2019201053)。

摘　　要：场助光电阴极与通常的负电子亲和势光阴极相比,能显著延长长波阈值,因此在近红外光探测中有着广阔的应用前景。本文利用二维连续性方程建立了n-InP/p-InP/p-InGaAs场助光阴极的电子发射模型。通过模型模拟得到了电子发射电流,并计算了外量子效率。分析了不同偏压下外延层的掺杂浓度和厚度对量子效率的影响,根据仿真结果及制备条件限制,确定了阴极外延结构的最佳参数:n-InP接触层的掺杂浓度为1×10^(19)/cm^(3),厚度为0.2μm;p-InP发射层的掺杂浓度为2.2×10^(18)/cm^(3),厚度为25 nm;p-InGaAs吸收层的掺杂浓度为5×1017/cm,,厚度为3μm。对电极和发射面的宽度进行了模拟,发射单元表面的宽度最佳范围为5~8μm,并分析了不同偏压下电极宽度和发射面宽度对量子效率的影响。为场助光电阴极的结构设计和应用提供了理论基础,有利于场助光电阴极的制备。n-InP/p-InP/p-InGaAs场助光电阴极有效提高了发射电流效率,室温5 V偏压下外量子效率在1.55μm处最大值为17.2%。Compared with the common negative electron affinity photocathode,the field-assisted photocathode can significantly extend the long-wavelength threshold,so it has a broad application prospect in nearinfrared light detection.In this work,the electron emission model of n-InP/p-InP/p-InGaAs field-assisted photocathode was established by using the two-dimensional continuity equations.The electron emission current was obtained by model simulation,and the external quantum efficiency was calculated.The influence of the doping concentration and thickness of the epitaxial layer on the quantum efficiency under different bias voltages was analyzed.According to the simulation results and the limitations of the preparation conditions,the optimal parameters of the cathode epitaxial structure were determined:the doping concentration and the thickness of the n-InP contact layer are 1×10^(19)/cm^(3) and 0.2μm,respectively;the doping concentration and the thickness of the p-InP emission layer are 2.2×10^(18)/cm^(3) and 25 nm,respectively;the doping concentration and the thickness of the p-InGaAs absorber layer are 5×1017/cm^(3) and 3μm,respectively.The widths of the electrode and the emission surface were simulated,and the optimal range of the width of the surface of the emitting unit was 5~8μm,and the effects of the electrode width and the width of the emission surface on the quantum efficiency under different bias voltages were analyzed.Simulation results provide a theoretical basis for the structure design and applications of the fieldassisted photocathode and are beneficial to the preparation of the field-assisted photocathode.The n-InP/p-InP/p-InGaAs field-assisted photocathode effectively improves the emission current efficiency,and the external quantum efficiency reaches a maximum of 17.2%at 1.55μm under a 5 V bias at room temperature.

关 键 词：光电阴极 量子效率 场助 INGAAS 

分 类 号：TN362[电子电信—物理电子学]