Analysis of the detectivity for triple-layer heterojunction GaSb/GaInAsSb infrared detectors

Abstract

In this paper, the detectivity is calculated and analyzed with the front-or backside illuminated case for both N-GaSb/p2-Ga0.8In0.2As0.19Sb0.8 1/p1-Ga0.9In0.1As0.09Sb0. 91 and N1-GaSb/n2-Ga0.9In0.1As0.09 Sb0.91/p-Ga0.8In0.2As0.19Sb 0.81 infrared photovoltaic detectors, respectively. The analysis results show that the main absorption appears in the p-type Ga0.8In0.2As0.19Sb0.81 material with either front- or backside illuminated case for above two structures. In each structure, the carrier concentration obviously affects the detectivity. The carrier concentration in the wide-bandgap material for the isotype heterojunction should be reduced as low as possible to reduce the tunneling rate at the isotype heterointerface. Moreover, the change of the detectivity with the p-side surface recombination velocity for the N1-n2-p structure is more sensitive than that with the p1-side surface recombination velocity for the N-p2-p1 structure. In the N-p2-p1 structure with the incident light from the p1-side surface, two-color detection is achieved. © 2003 Elsevier Science Ltd. All rights reserved.