Advanced InAs/GaSb superlattice photovoltaic detectors for very long wavelength infrared applications

Abstract

We report on the temperature dependence of the photoresponse of very long wavelength infrared type-II InAs/GaSb superlattice based photovoltaic detectors grown by molecular-beam epitaxy. The detectors had a 50% cutoff wavelength of 18.8 μm and a peak current responsivity of 4 A/W at 80 K. A peak detectivity of ${\text{4.5×10}}^{10}\hspace{0.5em}{\mathrm{cm Hz}}^{\text{1/2}}/\mathrm{W}$ was achieved at 80 K at a reverse bias of 110 mV. The generation–recombination lifetime was 0.4 ns at 80 K. The cutoff wavelength increased very slowly with increasing temperature with a net shift from 20 to 80 K of only 1.2 μm.