Research of NEA GaN photocathode performance parameters on the effect of quantum efficiency

Based on the negative electron affinity (NEA) GaN ultraviolet photocathode has high sensitivity, small dark emission, concentrative energy distribution of the launched electron, wide direct band gap, high quantum efficiency launch, solar blind response and so on, it is the extremely ideal new ultraviolet photocathode. In recent years it has been widely applied in the weak ultraviolet survey domain such as scientific research, military, outer space, environmental protection and so on
^[1]
. The quantum efficiency is an important parameter it attributes the photocathode characteristic and makes us understand thoroughly the photoelectric emission mechanism. Quantum efficiency formula of reflective and transmission GaN optoelectronic cathode can be obtained by solving the diffusion equation of heat electron consistency, through the theoretical formula we can further study the effect of P, electronic diffusion length L
D
, absorption coefficient α, compound rate of back interface S
v
and thickness of cathode transmit layer Te as the cathode performance parameters to Quantum efficiency
^{[2 ∼ 4]}
.