Far-infrared photoresponse of the InAs/GaInSb superlattice

We describe the growth and characterization of the InAs/GaInSb superlattice on GaSb substrates. We present far-infrared (λ∼10 μm) photoabsorption and photoconductivity spectra which are in good agreement with theoretical predictions for the photoresponse of this spatially indirect superlattice. We report time-resolved photoconductivity measurements in which two response times are observed. We interpret the fast, 2 ns decay as resulting from electron-hole recombination via deep defect levels and the slow, 2 μs decay as resulting from recombination of a small fraction of the photogenerated minority carriers which become trapped at a defect site.