Growth and photo-electronic characteristics of short/mid wave dual-band infrared detectors based on GaSb bulk and InAs/GaSb superlattices

Abstract

In this paper, we demonstrate a bias-selective short/mid wave dual-band infrared detector based on GaSb bulk materials and InAs/GaSb type-II superlattices with 50% cutoff wavelengths of 1.55 μm and 4.62 μm, respectively. At 77 K, the short wave channel exhibited a peak quantum efficiency of 35.86% at 1.43μm and a dark current density of 8.41 × 10−5A/cm2 under the forward 5.0 V bias, thereby providing a Johnson-noise-limited detectivity of 7.63 × 1011cm · Hz1/2/W. The mid-wave channel showed a quantum efficiency of 10.45% at 4.0μm and dark current density of 4.17 × 10−3A/cm2 under -1.35 V bias, resulting in a detectivity of4.05 × 1010cm · Hz1/2/W. The cross-talk was very low in the short wave channel, but existed in the mid wave channel originated from the contribution of the residual built-in electric field in the short wave channel. Furthermore, the schematic band alignment of N-I-P-P-I-N back-to-back structure was also discussed for further optimization.