Type II Superlattices for LWIR Detectors and Focal Plane Arrays

Long wavelength infrared (LWIR) imaging sensors are needed for next generation ballistic missile defense programs. Type II InAs/GaSb superlattices represent the most promising material system capable of delivering a more affordable and producible focal plane array (FPA) technology than the current technology, while at the same time exhibiting similar or better performance. It also offers unique design flexibility for new innovative detector structures. At present, one of the main challenges in achieving this potential is the minimization of the dark current, which is the aim of this Phase II project. To do so, it is proposed to design novel LWIR Type II superlattice structures with optimum absorbing and contact layer thicknesses and doping, to establish optimum growth conditions to achieve the highest material quality and to match the device designs, and to fabricate and test Type II superlattice photodetectors and arrays, correlating to growth conditions and processing techniques.