Comparative research on GaAs photocathodes before and after activation

Abstract

Obtaining higher quantum efficiency and more stability has been an important developing direction in the investigation of GaAs photocathodes. By solving the one-dimensional diffusion equation for no-equilibrium minority carriers of reflection-mode GaAs photocathode materials, we can get the equations of the surface photovoltage curve before activation and the spectral response curve after activation for uniform and exponential doping GaAs materials. Through experiments and fitting calculations for two doping structural materials designed by us, the parameters of the body materials are exactly measured by the surface photovoltage curves, and the curves for surface escape probability are also accurately fitted by the comparative research before and after activation. The differences for the fitting results of two doping structures are also well analyzed. This comparative research can form a closed-loop research for GaAs photocathodes and will help us to deeply study the varied doping structures and optimize Cs-O activation technology for GaAs photocathodes in the future.