Integration of an InSb photodetector on Si via heteroepitaxy for the mid-infrared wavelength region.

In this study, InSb p-i-n photodetectors with In0.82 Al0.18 Sb barrier layers were grown on a (100) 6° offcut Si substrate by heteroepitaxy via an AlSb/GaSb buffer. Based on an interfacial misfit array growth mode, the dislocations at the GaSb/Si and InSb/AlSb interfaces accommodated the lattice mismatch. The In0.82 Al0.18 Sb barrier layer increased the 77 K R0 A of the detector. From 180 K to 300 K, the generation-recombination mechanism dominated the dark current generation in the detector and surface leakage became dominant below 120 K. The detector exhibited a 77 K responsivity of 0.475 A/W and a Johnson-noise-limited detectivity of 3.08 × 109 cmHz1/2 W-1 at 5.3 µm.