An INAS/GANSB type II superlattice photodetector with forced p-type surface states

Abstract

The invention discloses an InAs / GaNSb type II superlattice photodetector with a forced p-type surface state. An absorption region of the photodetector is of a p type; an absorption region of a type IIsuperlattice photodetector includes an InAs layer and a GaSb layer; an N element is condensed in the GaSb layer; and the N element elevates a superlattice valence band top in an energy band structureof the absorption region to be higher than a surface state of the absorption region, or elevates the superlattice valence band top to be lower than the surface state but the distance from the surfacestate being less than 3kBT. A certain amount of N element is condensed into the GaSb layer of the absorption region of a traditional InAs / GaSb type II superlattice photodetector, and the N element elevates a superlattice valence band in the absorption region to be higher than the surface state of the absorption band, or elevates the superlattice valence band top to be lower than the surface statebut the distance from the surface state less than 3kBT, so that the surface state is changed into the p type being the same type as the absorption region; the surface SRH dark current is eliminated;and the performance of the detector is improved.

Description

technical field [0001] The invention belongs to the technical field of a second-type superlattice photodetector, and in particular relates to an InAs / GaNSb second-class superlattice photodetector with a forced p-type surface state. Background technique [0002] Surface states are local electronic energy states near the free surface of a solid or near the interface between solids. Because the atomic structure of the solid surface is different from the atomic structure in the body, the surface energy level is not only different from the energy band of the solid body, but also different from the energy level of the isolated atom. Semiconductor surface states are usually located in the fundamental bandgap or near the edge of the bandgap. The Fermi levels of the surface states of current InAs / GaSb photodetectors are all located in the forbidden band. The absorption region in common detectors is mostly weak p-type, so the minority carriers are electrons, which have a much higher...

AI Technical Summary

Problems solved by technology

The p-type absorption region and the above surface states will form a large number of SRH recombination centers, resulting in a large surface dark current and limiting the performance of the detector

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