Uncooled InAs-GaSb type-II infrared detectors grown on GaAs substrates for the 8-12-/spl mu/m atmospheric window

We report on the growth and characterization of type-II infrared detectors with an InAs-GaSb superlattice active layer for the 8-12-/spl mu/m atmospheric window at 300 K. The material was grown by molecular beam epitaxy on semi-insulating GaAs substrates. Photoconductive detectors fabricated from the superlattices showed 80% cutoff at about 12 /spl mu/m at room temperature. The responsivity of the device is about 2 mA/W with a 1-V bias (E=5 V/cm) and the maximum measured detectivity of the device is 1.3/spl times/10/sup 8/ cm.Hz/sup 1/2//W at 11 /spl mu/m at room temperature. The detector shows very weak temperature sensitivity. Also, the extracted effective carrier lifetime, /spl tau/=26 ns, is an order of magnitude longer than the carrier lifetime in HgCdTe with similar bandgap and carrier concentration.