Sulfide treatment passivation of mid-/long-wave dual-color infrared detectors based on type-II InAs/GaSb superlattices

The surface passivation of mid-/long-wave dual-color infrared detectors based on type-II InAs/GaSb superlattices(T2SLs) photodetectors employing diverse voltage and current conditions of sulfide treatment passivation was presented. The superlattices were grown on GaSb substrate by molecular beam epitaxy technology. The circle pixel devices in the diameter of 200 μm with 5 μm at mid-infrared and 14 μm at long-infrared 100% cutoff wavelength were fabricated. Compared to only SiO ₂ encapsulation passivation and unpassivated detectors, the dark current density, which takes into account surface leakage current, was reduced by approximately three orders of magnitude and the R0A-product was six times higher by sulfide treatment. Besides, detectors passivated through 22 V 15 mA sulfur treated, the responsivity of was 0.95A/W and QE was 0.44 at 2.6 μm. As for the wavelength of 5.3 μm, the responsivity and QE were 1.95 A/W and 0.45 severally.