Short wavelength infrared InAs/InSb/AlSb type-II superlattice photodetector

A photodetector based on InAs/InSb/AlSb type-II superlattice (T2SL) with thicknesses of 15, 1 and 4 monolayers respectively, was fabricated and characterized. The interface between InAs and AlAs of one InSb monolayer, increases the λcutoff to 3.3 μm, and improves the InAs/AlSb layer correlation and strain balancing. With a −0.5 V bias, the dark current at 300 and 200 K was 1.1 and 8.5 × 10−3 A/cm2 respectively, and the quantum efficiency at λ = 2.75 μm, for both 300 K and 200 K, was 34%. The detectivity was above 109 cm-Hz1/2/W for 300 K and above 1010 cm-Hz1/2/W for 200 K between 2.5 and 3 μm wavelength.