中国物理B ›› 2012, Vol. 21 ›› Issue (8): 87901-087901.doi: 10.1088/1674-1056/21/8/087901

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

The optimal thickness of transmission-mode GaN photocathode

王晓晖a b, 石峰a, 郭晖a, 胡仓陆a, 程宏昌a, 常本康b, 任玲b, 杜玉杰b c, 张俊举b   

  1. a Science and Technology on Low-Light-Level Night Vision Laboratory, Xi'an 710065, China;
    b Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China;
    c Department of Physics, Institute of Binzhou, Binzhou 256603, China
  • 收稿日期:2011-12-16 修回日期:2012-02-27 出版日期:2012-07-01 发布日期:2012-07-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 60871012), and the National Key Laboratory of Science and Technology Foundation on Low-Light-Level Night Vision, China (Grant No. J20110104), and the Research and Innovation Plan for Graduate Students of Jiangsu Higher Education Institutions (Grant No. CXZZ110238).

The optimal thickness of transmission-mode GaN photocathode

Wang Xiao-Hui (王晓晖)a b, Shi Feng (石峰)a, Guo Hui (郭晖)a, Hu Cang-Lu (胡仓陆)a, Cheng Hong-Chang (程宏昌)a, Chang Ben-Kang (常本康)b, Ren Ling (任玲)b, Du Yu-Jie (杜玉杰)b c, Zhang Jun-Ju (张俊举 )b   

  1. a Science and Technology on Low-Light-Level Night Vision Laboratory, Xi'an 710065, China;
    b Institute of Electronic Engineering and Optoelectronic Technology, Nanjing University of Science and Technology, Nanjing 210094, China;
    c Department of Physics, Institute of Binzhou, Binzhou 256603, China
  • Received:2011-12-16 Revised:2012-02-27 Online:2012-07-01 Published:2012-07-01
  • Contact: Chang Ben-Kang E-mail:bkchang@njust.mail.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 60871012), and the National Key Laboratory of Science and Technology Foundation on Low-Light-Level Night Vision, China (Grant No. J20110104), and the Research and Innovation Plan for Graduate Students of Jiangsu Higher Education Institutions (Grant No. CXZZ110238).

摘要: A 150-nm-thick GaN photocathode with an Mg doping concentration of 1.6× 1017cm-3 is activated by Cs/O in ultrahigh vacuum chamber, and quantum efficiency (QE) curve of negative electron affinity transmission-mode (t-mode) GaN photocathode is obtained. The maximum QE reaches 13.0% at 290 nm. According to the t-mode QE equation solved from the diffusion equation, the QE curve is fitted. From the fitting results, the electron escape probability is 0.32, the back-interface recombination velocity is 5× 104 cm·s-1, and the electron diffusion length is 116 nm. Based on these parameters, the influence of GaN thickness on t-mode QE is simulated. The simulation shows that the optimal thickness of GaN is 90 nm, which is better than the 150-nm GaN.

关键词: gallium nitride, transmission-mode, quantum efficiency, optimal thickness

Abstract: A 150-nm-thick GaN photocathode with an Mg doping concentration of 1.6× 1017cm-3 is activated by Cs/O in ultrahigh vacuum chamber, and quantum efficiency (QE) curve of negative electron affinity transmission-mode (t-mode) GaN photocathode is obtained. The maximum QE reaches 13.0% at 290 nm. According to the t-mode QE equation solved from the diffusion equation, the QE curve is fitted. From the fitting results, the electron escape probability is 0.32, the back-interface recombination velocity is 5× 104 cm·s-1, and the electron diffusion length is 116 nm. Based on these parameters, the influence of GaN thickness on t-mode QE is simulated. The simulation shows that the optimal thickness of GaN is 90 nm, which is better than the 150-nm GaN.

Key words: gallium nitride, transmission-mode, quantum efficiency, optimal thickness

中图分类号:  (Photoemission and photoelectron spectra)

  • 79.60.-i
72.80.-r (Conductivity of specific materials) 73.20.-r (Electron states at surfaces and interfaces) 73.61.-r (Electrical properties of specific thin films)