High operating temperature mid-wavelength infrared detectors based on InAs/InAsSb superlattices with electron block...

A high operating temperature mid-wavelength pBn infrared detector based on InAs/InAsSb superlattices with electron block interfacial graded doping is demonstrated. The photodetector exhibits saturated quantum efficiency from 77 K to 250 K under zero bias, requiring a -80 mV bias to fully extract photocurrent at 290 K. Under zero bias, the device achieves a peak responsivity of 1.69A/W at 150 K, corresponding to a quantum efficiency of 59.4%, and a detectivity of 1.24 × 10¹²cm·Hz^1/2/W at a cutoff wavelength of 5.0 µm. The dark current density of the pBn detector decreases from generation-recombination current limited 5.94 × 10^-5A/cm² to surface leakage current limited 2.95 × 10^-5A/cm² via the interfacial graded doping layer, resulting in a fitted generation recombination dark current of 1.37 × 10^-6A/cm². At 290 K, the cutoff wavelength extends to 6.2 µm, with a dark current density of 9.35 × 10^-2A/cm² and a peak quantum efficiency of 61.8% at 3.5 µm, leading to a specific detectivity of 9.87 × 10⁹cm·Hz^1/2/W. The dark current of the interfacial graded doping device is lower than the prediction of Rule 07 at a temperature higher than 190 K, demonstrating the great potential of the InAs/InAsSb pBn photodetector for room temperature operation.