Design of InAs/Ga(In)Sb superlattices for infrared sensing

New infrared detector materials with high sensitivity, multi-spectral capability, improved uniformity and lower manufacturing costs are required for numerous infrared sensing applications. One material system has shown great theoretical and experimental promise for these applications: InAs/InxGa1−xSb type-II superlattices. These superlattices offer a large design space for adjusting not only the energy band gap of the material but also the band structure. The infrared properties of several sets of designs of InAs/GaSb superlattices were studied. These designs covered the mid-infrared spectral band from 3 to 6 μm. Optimization design rules were explored. The infrared photoresponse spectra, combined with 8×8 k·p envelope function approximation modeling of superlattice band gaps and absorption spectra, provide insight into the underlying physics behind the optimized design of these materials.