Mid-infrared InAs0.79Sb0.21-based nBn photodetectors with Al0.9Ga0.2As0.1Sb0.9 barrier layers, and comparisons with InAs0.87Sb0.13 p-i-n diodes, both grown on GaAs using interfacial misfit arrays

InAs 0.79Sb0.21-based nBn photodetectors were fabricated on a GaAs substrate, using the interfacial misfit array growth mode. Reductions in the dark current density of more than two orders of magnitude at 300 K and more than six orders of magnitude at 200 K were found, in comparison with an InAs 0.87Sb0.13 p-i-n diode. At −0.5 V applied bias, the dark currents were found to be diffusion limited above 150 K. Background limited infrared photodetection and R0A values in excess of 106 Ωcm2 were observed at 150 K. Spectral response measurements revealed a cut-off wavelength of 5.3 μm at 200 K