Room-temperature InAsSb photovoltaic detectors for mid-infrared applications

Abstract
Novel noncryogenic InAsSb photovoltaic detectors grown by molecular beam epitaxy are proposed and demonstrated. The quaternary alloy In0.88Al0.12As0.80Sb0.20 is introduced as a wide bandgap barrier layer lattice matched to the GaSb substrate. The valence band edge of In0.88Al0.12As0.80Sb0.20 nearly matches with InAs0.91Sb0.09, leading to more efficient transport of photogenerated holes. The resulting mid-infrared photovoltaic detector exhibits a 50% cutoff wavelength of 4.31 mum and a peak responsivity of 0.84 A/W at room temperature. High Johnson-noise-limited detectivity (D*) of 2.6times109 cmmiddotHz1/2/W at 4.0 mum, and 4.2times1010 cmmiddotHz1/2/W at 3.7 mum are achieved at 300 K and 230 K, respectively