Monolithic Integration of InSb Photodetector on Silicon for Mid-Infrared Silicon Photonics

The InSb photodetector on a Si substrate acts as a signal receiver for the mid-infrared silicon photonics application to overcome the limitation of group IV semiconductors. In this paper, we demonstrated an InSb p-i-n photodetector with an InAlSb barrier layer grown on (100) silicon substrates via a GaAs/Ge buffer by molecular beam epitaxy. The lattice mismatch between InSb and GaAs was accommodated by an interfacial misfit array. The 50% cutoff detectable wavelength of this detector increased from 5.7 mu m at 80 K to 6.3 mu m at 200 K An 80 K detectivity of 8.8 X 10(9) cmHz(1/2) W-1 at 5.3 mu m was achieved with a quantum efficiency of 16.3%. The dark current generating mechanism of this detector is both generation-recombination and surface leakage above 140 K, while it is only surface leakage from 120 to 40 K.