Recombination lifetime in InAs–Ga1−xInxSb superlattices

Abstract

We report an experimental investigation of Shockley–Read and Auger lifetimes in InAs–Ga1−xInxSb and InAs–GaSb superlattices, based on measurements of the photoconductive response to excitation by a frequency-doubled CO2 laser (4.63 μm) at intensities up to 100 kW/cm2. Results at 77 K for low excitation levels yield Shockley–Read lifetimes between 0.13 and 6 ns. The scaling of the lifetime with carrier concentration also provides the first determinations of Auger coefficients in narrow-gap type II superlattices: γ3≊8×10−25 cm6/s at 300 K and γ3≊1.3×10−27 cm6/s at 77 K. The observed Auger lifetime at 77 K is two orders of magnitude longer than that in Hg1−xCdxTe with the same energy gap, which has highly favorable implications for InAs–Ga1−xInxSb superlattices in both IR detector and nonlinear optical applications.