Photoemission of AlGaN nanocone array cathodes for vacuum ultraviolet detectors

Abstract

The mushroom growth of ultraviolet detection, the high performance demands of solar-blind ultraviolet detectors have also grown. In our work, the AlGaN heterojunction nanocone array photocathode was used as the core device of the vacuum ultraviolet detector. The method of light absorption is obtained by FDTD Lumerical software, and the photoelectron transmission process is written in Matlab software by connecting the continuity equation and finite difference. The optical absorption model and photoemission model of AlGaN heterojunction nanocone array photocathode are established. The built-in electric field generated by the heterojunction structure promotes the drift diffusion of carriers, and the external electric field accelerates and deflects the flight of the emitted electrons. When the external electric field is rised from 0 V/μm to 2 V/μm, the collection efficiency of the nanocone array with an incident angle of 40° increases from 7.33% to 31.25%, and the electron collection ratio increases from 16.26% to 71.04%. These conclusions demonstrate the feasibility and effectiveness of this scheme, and provide theoretical guidance for the design and fabrication of high-performance solar-blind ultraviolet detectors.