Low Cost High Performance Efficient Uncooled of Thermoelectric Cooled Night Vision (NV) Infrared (IR) Imaging Systems

Type II superlattices (T2SL) represent a promising material system capable of delivering very producible, large-format broadband MWIR and LWIR focal plane arrays (FPAs). High temperature operation of current MCT based FPAs is limited by inherent defects in the II-VI material and strong Auger recombination. T2SLs are based upon mature III-V materials and would provide high material quality, lower substrate costs, lower Auger recombination rates and compatibility with industrial III-V foundry processes. However, current T2SL based FPAs are based on mesa-isolated pixels. The need for an etched trench to isolate the mesas limits the pixel pitch due to the challenges of the required deep mesa-etching and the need to subsequently passivate the mesa sidewalls. Passivation is especially problematic when the pixel pitch is scaled down, especially for LWIR FPAs and MWIR FPAs at temperatures >77K. One solution to this issue is to simply remove the mesa-sidewalls entirely by using planar structure. We present novel planar design for planar engineering for T2SL. The planar T2SL device is based on using diffusion approach to introduce the selective area doping for a p-on-n junction device. ĀThe small junction area of the planar diode also helps to reduce leakage currents and in raise the detector operating temperature. In Phase 1 single element planar photodiodes were demonstrated. In Phase II the focus is on arrays of MWIR and LWIR photodiodes for imaging applications.