Mechanism Of GaAlAs/GaAs Photocathode Components Material

As the photocathode used widely in the area of night vision, GaAs NEA photocathode owns many advantages, such as high quantum efficiency, small dark transmitter, centralized emission electron energy distribution and angular distribution, adjustable long-wave threshold and potential extended long-wave response. The third-generation night vision image intensifier constituted of transmission-mode GaAs photocathode, MCP and screen matches well with the night sky spectra and is playing an increasingly important role in the night vision field.This paper describes the development history of GaAs NEA photocathode and the two different ways of working, including reflection-mode and transmission-mode; then studies the variable doping methods, including uniform doping, gradient doping and exponent doping, shows the effect of different doping methods on photocathode performance and gives the quantum efficiency formula of photocathode in the different doping methods; after that, studies the main structure and performance optimization of the photocathode and illustrates the influence of material structure on photocathode performance mainly by analyzing the Al component of buffer layer; last, probes the inherent of the reflection-mode and transmission-mode photocathode by researching the different methods namely the reflection-mode and transmission-mode, gives the inherent in quantum efficiency of uniform doping and exponent doping and prepares for establishing and improving the theoretical system of GaAs NEA photocathode.