InAs/InAs1-xSbx type-II superlattices for high performance long wavelength infrared detection

High performance long-wavelength infrared nBn photodetectors based on InAs/InAs1-xSbx type-II superlattices on GaSb substrate have been demonstrated. The photodetector's 50% cut-off wavelength was similar to 10 mu m at 77 K. The photodetector with a 6 mu m-thick absorption region exhibited a peak responsivity of 4.47 A/W at 7.9 mu m, corresponding to a quantum efficiency of 54% at -90 mV bias voltage under front-side illumination and without any anti-reflection coating. With an R x A of 119 Omega.cm(2) and a dark current density of 4.4 x 10(-4) A/cm(2) under -90mV applied bias at 77 K, the photodetector exhibited a specific detectivity of 2.8 x 10(11) cm. root Hz/W. (C) 2014 AIP Publishing LLC.