Transmission-type GaN ultraviolet photocathode based on varied-doping structure and manufacturing method

Abstract

The invention discloses a transmission-type GaN ultraviolet photocathode based on a varied-doping structure and a manufacturing method. The cathode consists of a cathode transmission-type substrate layer made of sapphire, an AIN buffer layer, a p-shaped GaN photoemission layer with a varied-doping structure and a Cs or Cs / O activating layer from bottom to top; and the doping concentration of the p-shaped GaN photoemission layer is gradually lowered from the inner surface to the outer surface. In the invention, the transmission-type GaN ultraviolet photocathode is designed and prepared by adopting the varied-doping structure with the doping concentration changing from high to low from the inner surface to the outer surface; the varied-doping mode is utilized to generate a built-in electric field which is used for helping photoelectrons to be transported to the surface in a GaN cathode body, so as to improve the in vivo transport efficiency and surface effusion rate of the photoelectrons and finally improve the photoemission quantum efficiency of the photocathode; and simultaneously, the GaN photocathode has better longwave ultraviolet response ability, and all the improvements of the photoemission property rely on the built-in electric field auxiliary effect caused by varied-doping.

Description

technical field [0001] The invention relates to the technical field of ultraviolet detection materials, in particular to a transmissive GaN ultraviolet photocathode based on a variable doping structure based on a combination of semiconductor material doping technology, semiconductor material epitaxy technology and ultra-high vacuum surface activation technology and a manufacturing method. Background technique [0002] In recent years, with the improvement of GaN material preparation technology, p-type doping technology and the development of ultra-high vacuum technology, GaN UV photocathode is becoming a new type of high-performance UV photocathode. The surface of this cathode has a negative electron affinity (NEA). Compared with the traditional positron affinity UV photocathode and solid-state UV detection devices, the GaN UV photocathode shows high quantum efficiency, small dark emission, and UV-visible light suppression. It has many advantages such as high ratio, good sta...

AI Technical Summary

Problems solved by technology

Although the photoemission efficiency of the cathode can be improved by properly selecting the doping concentration, this compromise is limited to the material itself, which has great limitations and cannot significantly improve the photoemission performance of the cathode.

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