Development of Type-II Superlattices for Two-Color Focal Plane Arrays

High performance single-band focal plane arrays (FPAs) are sometimes unable to discriminate a target from its background when they present similar infrared radiation at a given wavelength which may occur even if the temperatures of the objects are different. Two-Color FPAs offer an additional wavelength that allows easy identification in such cases. Large-format dual-band FPAs are highly needed for next generation military applications. Current FPAs (eg. HgCdTe or Quantum Well Photodetectors) face fundamental and technological challenges when aiming for this new requirement. Type-II superlattices have been proposed as a viable technology and have already shown equivalent or better performance in single color detectors. In this project, we propose to continue the development of Type-II superlattices with Phase I demonstrating dual-band detectors based on Type-II superlattices, with equivalent performance as the state-of-the-art single color devices. The work will also consider the compatibility of dual-band Type-II superlattices detectors with large format ROICs designed and developed for dual-band FPAs. The development of material growth for large size wafers and of fabrication procedure for two-color arrays will also be addressed in this Phase I program to demonstrate the viability of Type-II superlattice technology. In Phase-II, 512x512 or dual-band FPAs will be delivered.