Research Activity on Type II InAs/GaSb Superlattice for LWIR Detection and Imaging at the Center for Quantum Devices.

Type II superlattice photodetectors have recently experienced significant improvements in both theoretical structure design and experimental realization. Empirical Tight Binding Method was initiated and developed for Type II superlattice. A new Type II structure, called M‐structure, was introduced and theoretically demonstrated high RoA, high quantum efficiency. Device design and growth condition were optimized to improve the performance. As a result, a 54% quantum efficiency, a 12 Ohm.cm2 RoA were achieved for 11 μm cut‐off photodetector at 77 K. Effective surface passivation techniques for MWIR and LWIR Type II superlattice were developed. FPA imaging at MWIR and LWIR were demonstrated with a capability of imaging up to room temperature and 211 K respectively. The noise equivalent temperature difference presented a peak at 50 mK for MWIR FPA at 121 K and 26 mK for LWIR FPA at 81 K.