High-operating temperature InAsSb/AlSb heterostructure infrared detectors grown on GaAs substrates by molecular beam epitaxy

Abstract

InAsSb/AlSb barrier detectors were grown on (100) semi-insulating GaAs substrates by a molecular beam epitaxy. We compare the performance of two detectors with different active layers denoted as p + BppBpN + and p + Bpnn + . InAs0.81Sb0.19 absorber allows to operate up to 5.3-μm cut-off wavelengths at 230 K. p + Bpnn + detector (n-type absorber) exhibits diffusion-limited dark currents above 200 K. AlSb barrier provides low dark currents and suppresses surface leakage currents. With a value of 0.13 A / cm2 at 230 K, the current is of about an order of magnitude larger than determined by the “Rule 07.” Dark currents of p + BppBpN + detector (p-type absorber) are much higher due to a contribution of Shockley–Read–Hall mechanisms. On the other hand, a device with a p-type absorber exhibits the highest value of current responsivity, up to 2.5 A / W, pointing out that there is a tradeoff between dark current performance and quantum efficiency.