InAs/GaSb type-II superlattice optical detector having forced n-type surface state

Abstract

The invention discloses an InAs / GaSb type-II superlattice optical detector having a forced n-type surface state. The InAs / GaSb type-II superlattice optical detector has an n-type absorption region. Inthe energy band structure of the absorption region, the surface state of the absorption region is located below a superlattice conduction band bottom and a gap between the surface state of the absorption region and the superlattice conduction band bottom is less than 3kBT, or the surface state is above the superlattice conduction band bottom, wherein kB is a boltzmann constant, and T is the operating temperature of the InAs / GaSb type-II superlattice optical detector. According to the InAs / GaSb type-II superlattice optical detector of the present invention, the surface state in the energy bandstructure is located over the superlattice conduction band bottom, or is located below the superlattice conduction band bottom and has a distance less than 3kBT to the superlattice conduction band bottom. Thus, the surface state changes to the n type, which is the same as that of the absorption region, thereby eliminating the surface SRH dark current and improving the performance of the detector.

Description

technical field [0001] The invention belongs to the technical field of InAs / GaSb type II superlattice photodetectors, in particular to an InAs / GaSb type II superlattice photodetector with a forced n-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 InAs / GaSb detectors is mostly weak p-type, in which the minority carriers are electrons, which have greater mo...

AI Technical Summary

Problems solved by technology

However, 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, which limits the performance of the detector.

When the absorption region is of the same type as the surface state, the SRH recombination center will be significantly suppressed, but it is difficult to obtain the p-type surface state in the InAs / GaSb type II superlattice material system

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