Gan nanowire array photocathode based on field-assisted index doping structure

Abstract

The invention provides a GaN nanowire array photocathode based on a field-assisted index doping structure, including a transparent input window, an index doped GaN nanowire array photocathode and a metal grid; an index doped GaN nanowire array photocathode front end The surface is close to the transparent input window, and a metal grid is arranged at a predetermined distance behind the exponentially doped GaN nanowire array photocathode. The exponentially doped GaN nanowire array photocathode includes a substrate, an unintentionally doped AlN buffer layer, a p-type Exponentially doped GaN nanowire array photoemission layer and Cs / O active layer, the substrate and the transparent input window are placed close to each other, the unintentionally doped AlN buffer layer is close to the rear end of the substrate, p-type exponentially doped GaN The nanowire array photoemissive layer includes several GaN nanowires and each GaN nanowire is arranged on the back end of the unintentionally doped AlN buffer layer, the Cs / O active layer is wrapped on the surface of the GaN nanowire, and the metal grid is connected to the circuit to form a uniform power grid.

Description

technical field [0001] The invention relates to a photoelectric emission technology, in particular to a GaN nanowire array photocathode based on a field-assisted index doping structure. Background technique [0002] Negative electron affinity (NEA) GaN photocathode is used in high-density spin-polarized electron sources and ultraviolet detection due to its unique advantages such as high quantum efficiency (QE), small dark current, high polarizability, and concentrated electron emission energy. and other fields. However, the development of photocathode is limited to thin-film materials, and the quantum efficiency cannot be achieved due to the contradiction between photon absorption and electron diffusion on the thickness of the material. Nanomaterials can break through the application limitations of thin film materials. The nanowire array structure has excellent optical absorption characteristics, which greatly reduces the reflection of photons on the surface of the materia...

AI Technical Summary

Problems solved by technology

In the process of studying the quantum efficiency of each facet of the GaN nanowire photocathode, it is found that there is still a problem: when the light is incident on the nanowire array and undergoes repeated refraction, the maximum collection of the escaped electrons after being absorbed by the nanowires

The photoelectrons on the sidewalls around the nanowires cannot achieve a good collection effect, resulting in a significantly lower quantum efficiency than the top, mainly because of the reabsorption of adjacent nanowires.

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