An InAsSb/AlSb heterostructure photovoltaic detector structures were grown on a (100) semi-insulating GaAs substrates by a molecular beam epitaxy. We compare the performance of two detectors with a different type of absorbing layers, denoted p+BppBpn+ and p+Bpnn+. InAs0.81Sb0.19 absorption layers allow for a operation 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 a low values of dark currents and allows a suppression of surface leakage current. With a value of 0.13 A/cm2 at 230 K, the current is less than an order of magnitude larger than those determined by the "Rule 07" for HgCdTe detectors. 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, device with a p-type absorber shows highest values of current responsivity, up to 2.5 A/W, point out that there is a trade-off between dark current performance and quantum efficiency.
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