Varshni parameters for InAs/GaSb strained layer superlattice infrared photodetectors

Abstract

The temperature-dependent behaviour of the bandgap of mid- and long-wavelength as well as dual-colour (mid-/long-wavelength) infrared detectors based on InAs/GaSb strained layer superlattices (SLSs) with p-i-n and nBn designs has been investigated with temperature-dependent absorption, photoluminescence and spectral response techniques. Values of Varshni parameters, zero temperature bandgap E 0 and empirical coefficient α, were extracted and tabulated. The MWIR and LWIR superlattice detectors showed a temperature change of 0.325 meV K −1 and 0.282 meV K −1 , respectively. These values are a factor of two lower than that of HgCdTe and InSb, making them attractive for higher operating temperatures.