High Operating Temperature MWIR FPA Camera Based on M-Structure Type-II Superlattices

Current high-performance MWIR FPAs require cooling with a cryo-cooler to ~77 K, the cryo-cooler that limits the system lifetime. If the FPA operation temperature can be raised to>170 K without sacrificing performance, then lower power and longer lifetime MWIR cameras should be possible. Type-II InAs/GaSb superlattices represent the most promising material system capable of delivering a camera operating above 170 K. High temperature operation of current MCT based FPAs is limited by inherent defects in the II-VI material and strong Auger recombination. Type-II is based upon more mature III-V materials and should give better material quality, lower substrate costs, and compatibility with industrial III-V foundry processes. Type-II has significantly lower Auger recombination rates, and using the superlattice, the band structure can be engineered to further suppress Auger recombination. This allows for lower dark currents at higher operating temperatures thereby allowing for the development of a camera that can potentially achieve MCT performance at 170 K or greater. In this proposed work we will systematically study MWIR Type-II and apply recent innovations in order to demonstrate improved performance and then develop high performance MWIR FPAs and ultimately deliver a low-power FPA camera system at the end of Phase II.