Feasibility of Long Wavelength Infrared Focal Plane Arrays Based on Type-II Superlattice Minority Electron Unipolar Architecture

Recent development of Antimonide-based Type-II superlattice infrared detectors has resulted in significant breakthroughs in terms of device performance as well as FPA imaging quality. Improvement in material quality and processing technique, as well as evolutionary modifications in device architecture have demonstrated the advantages of the material system over alternatives, and proven it as a viable candidate for the next generation infrared imaging. Yet, the performance of this material system has not reached its limits. In this project, we propose to further build upon the gap-engineering capability of Type-II superlattices to develop novel quantum device architecture called Minority Electron Unipolar Photodetector (MEUP). The design is a hybrid between conventional photoconductive and photovoltaic detectors and can benefit from the advantages of both configurations. The novel device architecture is expected to achieve high quantum efficiency while decreasing the dark current and the associated shot-noise. Material growth will be realized on 3"GaSb substrates and optimized for highest quality and excellent uniformity across the wafer. Applying it to LWIR FPAs in Phase II, it is expected to achieve a quantum efficiency above 60% and a dark current density below 1 uA/cm2 at operating temperatures higher than 65 K.