The paper presents electrical and optical properties of interband cascade infrared photodetectors with InAs/GaSb type-II superlattice absorbers. We compare the detection parameters of detectors grown on the native GaSb substrate and lattice-mismatched GaAs substrate and seek solutions to enhance device performance, specifically with using an optical immersion. The detectors grown on GaAs have better detection parameters at room temperature, but, at lower temperatures, the misfit dislocations become more important, and detectors grown on GaSb become better.