Improvement of photoemission performance of a gradient-doping transmission-mode GaAs photocathode  

作　　者：张益军 牛军 赵静 熊雅娟 任玲 常本康 钱芸生 

机构地区：[1]Institute of Electronic Engineering and Optoelectronic Technology,Nanjing University of Science and Technology

出　　处：《Chinese Physics B》2011年第11期534-540,共7页中国物理B（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.60801036 and 61067001);the Key Science and Technology Project of Henan Province of China(Grant No.112102210202);the Research and Innovation Plan for Graduate Students of Jiangsu Higher Education Institutions of China(Grant No.CX09B_096Z)

摘　　要：Two types of transmission-mode GaAs photocathodes grown by molecular beam epitaxy are compared in terms of activation process and spectral response, one has a gradient-doping structure and the other has a uniform-doping structure. The experimental results show that the gradient-doping photocathode can obtain a higher photoemission capability than the uniform-doping one. As a result of the downward graded band-bending structure, the cathode performance parameters, such as the electron average diffusion length and the surface electron escape probability obtained by fitting quantum yield curves, are greater for the gradient-doping photocathode. The electron diffusion length is within a range of from 2.0 to 5.4μm for doping concentration varying from 10^19 to 10^18 cm^-3 and the electron average diffusion length of the gradient-doping photocathode achieves 3.2 μm.Two types of transmission-mode GaAs photocathodes grown by molecular beam epitaxy are compared in terms of activation process and spectral response, one has a gradient-doping structure and the other has a uniform-doping structure. The experimental results show that the gradient-doping photocathode can obtain a higher photoemission capability than the uniform-doping one. As a result of the downward graded band-bending structure, the cathode performance parameters, such as the electron average diffusion length and the surface electron escape probability obtained by fitting quantum yield curves, are greater for the gradient-doping photocathode. The electron diffusion length is within a range of from 2.0 to 5.4μm for doping concentration varying from 10^19 to 10^18 cm^-3 and the electron average diffusion length of the gradient-doping photocathode achieves 3.2 μm.

关 键 词：transmission-mode photocathode GRADIENT-DOPING Cs-O activation quantum yield 

分 类 号：O472.3[理学—半导体物理]