High-performance midwavelength infrared detectors based on InAsSb nBn design**Project supported by the National Key Technologies Research and Development Program of China (Grant No. 2018YFA0209104) and the Major Program of the National Natural Science Foundation of China (Grant No. 61790581).

Abstract

we report nBn photodetectors based on InAs0.91Sb0.09 with a 100% cut-off wavelength of 4.75 μm at 300 K. The band of an nBn detector is similar to that of a standard pin detector, but there is special wide bandgap AlAs0.08Sb0.92 barrier layer in the nBn detector, in which the depletion region of nBn detector exists. The nBn design has many advantages, such as low dark current and high quantum efficiency, because the nBn design can suppress the generation–recombination (GR) current that is the main composition of standard pin detector dark current. The constant slope of the Arrhenius plot of J0–1/T indicates the absence of the generation–recombination dark current. We fabricate an nBn detector with a quantum efficiency (QE) maximum of ∼ 60% under −0.2-V bias voltage. The InAsSb nBn detectors may be a competitive candidate for midwavelength infrared detector.