Bandgap engineered HgCdTe nano-crystal based hetero-junction infrared sensor

Advantage of remote-sensing in mid wave infrared (MWIR) spectral range (2μm-5μm) due to atmospheric transmission window. Dominant photon detectors in this range are single crystal InSb and HgCdTe, while cost of these detectors is very high and requires cooling around 80K to reduce dark current. Semiconductor Nano-Crystals or Quantum dots (QD) provide an alternative, combining the advantages of speed and Detectivity (D*) of quantum detectors with much reduced fabrication costs compared to single crystal epitaxial materials. This paper highlights synthesis of ternary alloy semiconductor Mercury-Cadmium-Telluride (HgCdTe) colloidal quantum dots and realization of HgCdTe/Si hetero-junction infrared detector sensitive in MWIR range at room temperature. The photo-response of the nano-crystal HgCdTe/Si heterojunction devices is found to have significant response in MWIR region at room temperature.