Research on quantum efficiency of reflection-mode GaAs photocathode with thin emission layer

Abstract

The conventional quantum efficiency formula for the reflection-mode GaAs photocathode is not applicable to the photocathode with a thin emission layer. The revised quantum efficiency formula has been solved from one-dimension continuity equations, in which the electrons generated in the GaAlAs buffer layer are considered. According to the revised formula, we analyze the impact of some relational performance parameters on the quantum efficiency, such as the thickness of emission layer, the interface recombination velocity etc. Besides, we use the revised and conventional formula to fit the experimental curves of two photocathodes which have the different-thickness emission layers respectively. The results show that compared with the conventional quantum efficiency formula, the revised formula is more suitable to the reflection-mode GaAs photcathode with a thin emission layer, and the GaAlAs buffer layer takes part in the photoemission.