Design and fabrication of high-performance LWIR photodetectors based on Type-II superlattices

Antimonide-based Type-II superlattices represent the most promising material system capable of delivering more producible, large-format, reduced pixel pitch, long-wavelength infrared (LWIR) focal plane arrays (FPAs) for persistent surveillance applications. 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 study both InAs/GaSb and strain-balanced InAs1-xSbx/InAs Type-II superlattices for LWIR detection and imaging. After this study, it is expected to achieve a superlattice design with longer minority carrier lifetime. Longer minority carrier lifetime results in lower dark current, lower noise, higher operation temperature, and higher quantum efficiency. Applying this superlattice design to LWIR FPAs, it is expected to achieve higher quantum efficiency, lower dark current, higher specific detectivity (D*) and reduced Noise Equivalent Temperature Difference (NEDT).