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 mu m). 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 x 10(10) cm Hz(1/2) W-1 at about 3.5 mu m. (c) 2005 WfLEY-VCH Verlag GmbH & Co. KGaA, Weinheim.