"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Resolution characteristics of transmission-mode exponential-doping GaN photocathodes

HONGGANG WANG1,2,3,4,* , JUNJU ZHANG2,4, GANG WANG1, QINFENG XU1, JIAN LIU2,4, XUGUANG ZHAO1

Affiliation

  1. School of Information and Electrical Engineering, Ludong University, 264025, Yantai, CHN
  2. Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology, 210094, Nanjing, CHN
  3. Jiangsu Key Laboratory of Spectral Imaging & Intelligent Sense, 210094, Nanjing, CHN
  4. School of Electronic and Optical Engineering, Nanjing University of Science and Technology, 210094, Nanjing, CHN

Abstract

According to the electron transport equation for the transmission-mode uniform-doping GaN photocathode, we have obtained the electron transport equation for the transmission-mode exponential-doping GaN photocathode. And then through solving this equation, the expression of modulation transfer function for an exponential-doping GaN photocathode is determined. Subsequently, the resolution characteristics of transmission-mode exponential-doping and uniform-doping GaN photocathodes are calculated and comparatively analyzed. Simultaneously, the quantum efficiencies of both GaN photocathodes are given. These calculated results show that the exponential-doping structure can upgrade remarkably not only the resolution but also the quantum efficiency of a negative electron affinity GaN photocathode, compared with the uniform-doping structure. This upgradation differs from the approach for high resolution by shortening the thickness of emission layer Te and the diffusion length of electron Ld or by increasing the recombination velocity of back-interface V S , which leads to a low quantum efficiency. Furthermore, the upgradation of resolution and quantum efficiency for a transmission-mode exponential-doping GaN photocathode result mainly from the facilitation of the electron transport and constraint of the lateral diffusion by the built-in electric field..

Keywords

GaN photocathode, Resolution, Exponential-doping, Modulation transfer function.

Submitted at: Aug. 3, 2016
Accepted at: Aug. 9, 2017

Citation

HONGGANG WANG, JUNJU ZHANG, GANG WANG, QINFENG XU, JIAN LIU, XUGUANG ZHAO, Resolution characteristics of transmission-mode exponential-doping GaN photocathodes, Journal of Optoelectronics and Advanced Materials Vol. 19, Iss. 7-8, pp. 522-527 (2017)