Abstract
Resolution of a reflection-mode GaAlAs photocathode which is efficiently characterized by modulation transfer function (MTF)
is primarily governed by electron lateral diffusion in this photocathode. As several crucial parameters for the GaAlAs
photocathode, the length of electron diffusion LD, the thickness of emission layer Te, the coefficient of optical absorption α, and
the recombination velocity at back-interface SV has a significant effect on the degree of lateral diffusion. To obtain a high
resolution, by establishing an appropriate model of MTF for reflection-mode exponential-doping GaAlAs photocathode, the
effect of LD, Te, α, and SV on corresponding MTF and quantum efficiency for exponential-doping and uniform-doping
Ga0.37Al0.63As photocathodes has been researched in detail. And then we have discussed the dependence of electron lateral
diffusion on LD, Te, α, and SV. The calculated results demonstrate that the reflection-mode exponential-doping Ga0.37Al0.63As
photocathode has a great potentiality in achieving high resolution and high quantum efficiency, compared with its counterpart
employed uniform-doping structure. It is mainly because that electron lateral diffusion in this photocathode is bound by electric
field which is formed by exponential-doping structure. In practice, for a given reflection-mode exponential-doping
Ga0.37Al0.63As photocathode, a compromise between high resolution and high quantum efficiency must be made.
Keywords
Electron lateral diffusion, Reflection-mode, Exponential-doping, GaAlAs photocathode, Modulation transfer function.
Citation
HONGGANG WANG, LILI WANG, JINGUANG HAO, JIAN LIU, YAOZHANG SAI, YANG CAO, Effect of electron lateral diffusion in the reflection-mode exponential-doping GaAlAs photocathode on resolution, Optoelectronics and Advanced Materials - Rapid Communications, 17, 11-12, November-December 2023, pp.512-518 (2023).
Submitted at: Sept. 11, 2023
Accepted at: Dec. 4, 2023