Enhanced photoemission by GaInAsSb photocathode with the nanopillar array and back surface reflector

Abstract GaSb-based photocathodes is widely used in fields such as TPV, solar radiation detection due to their fast response, high long-wave sensitivity. However, thin-film structure’s low absorptance is a major factor limiting their further application. We designs a photocathode with nanopillar arrays and back surface reflector structure, which can bind light to a thin active layer and significantly improve the properties of the cathode. Using the FDTD method, simulated the impact of structural parameters of the NPAs on the absorptance and emission efficiency of the active region, achieving an optimized structure with the best performance. Additionally, we discussed the effect of assistance electric field on the performance of the cathode, and found the electric-field can improve the photoelectron EQE. When the field strength exceeds 10 kV cm −1 , the EQE is over 18%, which is notably superior to BSR structures. Its response time in the infrared band is below 50 ps, achieving ultrafast response.