Optimization of InAsSb photodetector for non-cryogenic operation in the mid-infrared range

We present an InAsSb interband photodetector grown by molecular beam epitaxy on GaSb substrate which operates in the mid-infrared domain (3–5 µm). To achieve uncooled high performance detection, the design of the structure was optimized to reduce the noise-inducing currents due to generation-recombination processes and diffusion currents. The technological procedure was further improved by using alkali sulfur passivation that suppresses surface leakage currents along the mesa edges. As a first result, the room temperature detectivity D* of the InAsSb photodiode, extracted from measurements, is comparable to the commercial HgCdTe device with a detectivity equals to 1 × 1010 cm Hz1/2 W–1 at about 3.5 µm. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)