(Invited) InAs/InAs1-XSbx Type-II Superlattices for High-Performance Long-Wavelength Infrared Medical Thermography

Abstract

We present the demonstration of a high-performance long-wavelength infrared nBn photodetectors based on InAs/InAs1-xSbx type-II superlattices on GaSb substrate. The photodetector’s 50% cut-off wavelength was ~10 mm at 77K. The photodetector with a 6 mm-thick absorption region exhibited a peak responsivity of 4.47 A/W at 7.9 mm, corresponding to a quantum efficiency of 54% at -90 mV applied bias voltage under front-side illumination and without any anti-reflection coating. With an R×A of 119 Ω·cm2 and a dark current density of 4.4×10-4 A/cm2 under -90 mV applied bias voltage at 77 K, the photodetector exhibited a specific detectivity of 2.8×1011 cm./W. This photodetector opens a new horizon for making infrared imagers with higher sensitivity for medical thermography.