Room-temperature InAsSb photovoltaic detectors for mid-infrared applications

Novel noncryogenic InAsSb photovoltaic detectors grown by molecular beam epitaxy are proposed and demonstrated. The quaternary alloy In_0.88Al_0.12As_0.80Sb_0.20 is introduced as a wide bandgap barrier layer lattice matched to the GaSb substrate. The valence band edge of In_0.88Al_0.12As_0.80Sb_0.20 nearly matches with InAs_0.91Sb_0.09, 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 cmmiddotHz^1/2/W at 4.0 mum, and 4.2times10¹⁰ cmmiddotHz^1/2/W at 3.7 mum are achieved at 300 K and 230 K, respectively