Transmission-type GaN ultraviolet photocathode based on composition graded buffer layer

Abstract

The invention discloses a transmission-type GaN ultraviolet photocathode based on a composition graded buffer layer, the cathode consists of a double-polished c surface sapphire substrate, an AlxGa1-xN composition graded buffer layer, a p-type GaN emission layer and a Cs or Cs / O active coating from bottom to top; the AlxGa1-xN composition graded buffer layer consists of n unit layers, wherein n is greater than or equal to 3 and is less than or equal to 10; and Al composition in each layer of the n unit layers from bottom to top meets the need that x1)x2)... xn is less than or equal to 1 and is greater than or equal to 0.The buffer layer of the transmission-type GaN ultraviolet photocathode is designed and prepared by adopting the AlxGa1-xN in which the Al component content decreases gradually from 1 to 0, and growth interface stress between buffer a material and an emitting material is reduced by utilizing the composition graded mode, thus improving the interface characteristics of the transmission-type GaN ultraviolet photocathode, reducing the photoelectronic interface recombination rate and finally enhancing the photoemission quantum efficiency of the GaN ultraviolet photocathode.

Description

technical field [0001] The invention relates to the technical field of ultraviolet detection materials, in particular to an Al-based 1-x Ga x A transmissive GaN ultraviolet photocathode based on a graded composition buffer layer based on the combination of N ternary compound Al / Ga composition control technology and Ш-V group compound material epitaxy technology. 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. GaN UV photocathode has many advantages such as high quantum efficiency, small dark emission, high UV-visible light suppression ratio, good stability, and concentrated energy distribution of emitted electrons. It has great application potential in the field of UV detection. [0003] In practical applications, a photocathode with a transmissive structure ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the current situation that the existing transmissive AlN buffer layer does not match the lattice of the GaN emitting layer and the interface properties are not ideal, the present invention provides an Al-based 1-x Ga x N ternary compound Al / Ga composition control technology, Ш-V group compound material epitaxy technology and ultra-high vacuum surface activation technology are combined to improve the interfacial properties of the transmissive GaN photocathode buffer layer, and ultimately improve the photoemission of the photocathode Transmissive GaN UV photocathode based on composition graded buffer layer with quantum efficiency

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