LAUSR

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.