Nano-Passivation of GaSb/InAs Strained Layer Superlattices Infrared Detector

Long-wavelength infrared (LWIR) imaging has significant importance in military surveillance and target recognition, since human body radiation peaks in LWIR. Despite the enhanced wavelength coverage, the GaSb/InAs type-II Strained Layer Superlattice (SLS) detector still exhibits relatively high surface leakage current and its associated noises. With an industrially proven nano-material, we propose the nano-passivation of GaSb/InAs SLS and photodetector. The proposed solid-state nano-passivation technology is completely compatible with array integration. The resulting focal plane array (FPA) will have 15 micron or smaller pixel pitch, targeted 99.9% operable pixels, and 90% fill factor for greater than 50% external quantum efficiency. With minimized surface dark current, the SLS noise mechanisms will no longer be dominated by surface dark current at 77K. The nano-passivation layer will also have high device lifetime. Based on the proven feasibility of nano-passivation to minimize pixel dark current during Phase I, in Phase II we will design, fabricate and demonstrate a prototype large format reduced pixel pitch SLS FPA imager, which will be delivered to DoD Labs for evaluation and demonstration. During Phase III, we will manufacture and market the proposed camera to defense contractors for incorporation into military systems and for our own infrared spectroscopy products.