Midwave Infrared Quantum Dot Quantum Cascade Photodetector Monolithically Grown on Silicon Substrate

Mid-infrared photodetector based on submonolayer (SML) quantum dot quantum cascade structure monolithically grown on silicon substrate has been demonstrated in this paper. Both the optical and electrical characteristics of the SML quantum dot quantum cascade photodetectors (QD-QCD) were analyzed quantitatively. The performances of these devices were compared with that on native GaAs substrate. A large resistance-area (R(0)A) product of 1.13 x 10(7) Omega.cm(2) is achieved at 77 K for the silicon-based devices, which is only roughly one order less than that on GaAs substrate. The device shows a normal-incident peak responsivity of 0.59 mA/W under zero bias at the wavelength of 6.2 mu m at 77 K, indicating a photovoltaic operation mode. Johnson noise limited specific detectivity is 3 x 10(10) cm.Hz(1/2)/W at 77 K, with photoresponse up to 100 K. These results suggest that the silicon-based QD-QCD in this paper is a very promising candidate for large format mid-infrared focal plane array and mid-infrared silicon photonics applications.