Extended Short-Wave Infrared T2SL Detector Based on AlAsSb/GaSb Barrier Optimization

Extended short-wave infrared (eSWIR) detectors operating at high temperatures are widely utilized in planetary science. A high-performance eSWIR based on pBin InAs/GaSb/AlSb type-II superlattice (T2SL) grown on a GaSb substrate was demonstrated. It achieves the optimization of the device's optoelectronic performance by adjusting the p-type doping concentration in the AlAs₀.₁Sb₀.₉/GaSb barrier. Experimental and TCAD simulation results demonstrate that both the device's dark current and responsivity grow as the doping concentration riseing. Here, the bulk dark current density and bulk differential resistance area was extracted to calculate the bulk detectivity for evaluating the photoelectric performance of the device. When the barrier concentration is 1×1017 cm-3, the bulk detectivity is 2.1×1011 cm•Hz1/2/W, which is 256% higher than the concentration of 2×1018 cm-3. Moreover, at 300K (-10 mV), the 100% cutoff wavelength of the device is 1.9 μm, the dark current density is 9.48×10-6 A/cm2, and the peak specific detectivity is 7.59×1010 cm•Hz1/2/W (at 1.6 μm). The eSWIR detectors with low operating bias and low dark current density hold promise for being developed into high-performance imagers.