Bias-selectable dual-band mid-/long-wavelength infrared photodetectors based on InAs/InAs_1-xSb_x type-II superlattices

A high performance bias-selectable mid-/long-wavelength infrared photodetector based on InAs/InAs_1-xSb_x type-II superlattices on GaSb substrate has been demonstrated. The mid- and long-wavelength channels' 50% cut-off wavelengths were ∼5.1 and ∼9.5 μm at 77 K. The mid-wavelength channel exhibited a quantum efficiency of 45% at 100 mV bias voltage under front-side illumination and without any anti-reflection coating. With a dark current density of 1 × 10^-7 A/cm² under 100 mV applied bias, the mid-wavelength channel exhibited a specific detectivity of 8.2 × 10¹²cm· Hz/W at 77 K. The long-wavelength channel exhibited a quantum efficiency of 40%, a dark current density of 5.7 × 10^-4 A/cm² under -150 mV applied bias at 77 K, providing a specific detectivity value of 1.64 × 10¹¹cm· Hz/W.