We report on the growth and characterization of type-II infrared detectors with an InAs-GaSb superlattice active layer for the 8-12-μm 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 μm 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 1.3×108 cm·Hz1/2/W at 11 μm at room temperature. The detector shows very weak temperature sensitivity. Also, the extracted effective carrier lifetime, τ = 26 ns, is an order of magnitude longer than the carrier lifetime in HgCdTe with similar bandgap and carrier concentration.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Electrical and Electronic Engineering