Abstract

Using the modulation transfer function obtained by establishing and solving the two-dimensional continuity equation, we have calculated and comparatively analyzed the resolution characteristics of transmission-mode exponential-doping and uniform-doping ${\mathrm{Ga}}_{0.37}{\mathrm{Al}}_{0.63}\mathrm{As}$ photocathodes. The calculations show that compared with a uniform-doping ${\mathrm{Ga}}_{0.37}{\mathrm{Al}}_{0.63}\mathrm{As}$ photocathode, the exponential-doping structure can significantly improve not only the resolution, but also the quantum efficiency of the photocathode. This improvement is different from the approach for high resolution by reducing the emission layer thickness $T_e$ and electron diffusion length $L_D$, or by increasing the recombination velocity of the back-interface, $S_V$, which results in low quantum efficiency. Furthermore, the improvement in resolution and quantum efficiency for the transmission-mode exponential-doping ${\mathrm{Ga}}_{0.37}{\mathrm{Al}}_{0.63}\mathrm{As}$ photocathodes is the result of the effect of the built-in electric field on electron transport and lateral diffusion.

© 2014 Optical Society of America

Resolution characteristics for reflection-mode exponential-doping GaN photocathode

Honggang Wang, Yunsheng Qian, Yujie Du, Yuan Xu, Liubing Lu, and Benkang Chang
Appl. Opt. 53(3) 335-340 (2014)

Stability of negative electron affinity Ga_0.37Al_0.63As photocathodes in an ultrahigh vacuum system

Xinlong Chen, Guanghui Hao, Benkang Chang, Yijun Zhang, Jing Zhao, Yuan Xu, and Muchun Jin
Appl. Opt. 52(25) 6272-6277 (2013)

Effect of lateral diffusion of photoelectrons in the reflection-mode varied-doping AlGaN photocathode on resolution

Honggang Wang, Junju Zhang, Dianli Hou, Jinguang Hao, Lili Wang, and Yaozhang Sai
Appl. Opt. 60(25) 7658-7663 (2021)

Resolution characteristics of graded doping and graded composition transmission-mode AlGaAs/GaAs photocathodes

Wenjuan Deng, Jijun Zou, Xincun Peng, Lin Feng, Zhifu Zhu, Weilu Wang, Yijun Zhang, and Benkang Chang
Appl. Opt. 54(6) 1414-1419 (2015)

Influence of exponential doping structure on the performance of GaAs photocathodes

Jun Niu, Yijun Zhang, Benkang Chang, Zhi Yang, and Yajuan Xiong
Appl. Opt. 48(29) 5445-5450 (2009)