Dark Current Analysis in Type-II InAs/GaSb Superlattice LWIR Detector with M-structure Barrier

Abstract

We designed a long-wave infrared detector using InAs/GaSb and InAs/GaSb/AlSb/GaSb superlattices and further studied the effect of some sensitive parameters on dark current characteristics. We utilize the numerical model to analyze the dark current characteristics of the contact layer and the absorption layer at different doping levels, and also calculate the dark current characteristics of the absorption layer and barrier layer at different thicknesses. By designing different absorption layer and barrier layer, we found that the detector has a hole barrier in the valence band, which effectively reducing the dark current level. Under the optimal detector structure, the dark current at low temperature is maintained at a relatively ideal level about 2.25×10-5 A/cm2 and the quantum efficiency is close to 42%.