Feasibility of High Operating Temperature MWIR Type-II FPAs

Current high-performance MWIR FPAs require cooling to ~77K. This generally requires the use of a cryocooler 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 at T >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 should be compatible 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 should allow for lower dark currents at higher operating temperatures thereby allow 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 pave the way for the development of a FPA camera is Phase II.