HgTe/CdTe Superlattice FTIR Detectors Optimized for the 300-to-1000 cm-1 Region

The 300-1000 cm-1 spectral region, commonly referred to as the fingerprint region, is rich in spectral signatures; also, blackbody emission at room temperature peaks in this region. Thus, high-resolution infrared (IR) detectors sensitive in this region are seriously needed for the remote sensing of weapons of mass destruction (WMD), especially nuclear weapons. However, existing IR detectors do not meet this need. Traditional mercury cadmium telluride (MCT) IR detectors suffer from serious difficulties, including losses and noise due to a rapid decay in the number of photo-excited carriers and large leakage currents. The existing alternative detectors, bolometers, have far too slow a response for many applications, and are bulky and heavy because they require cooling to liquid He temperatures. This project will combine the potential, but as yet not fully realized, advantages of HgTe/CdTe Type III superlattices (SLs) with device architectures that will allow operation at liquid nitrogen temperatures, in order to achieve high pixel-to-pixel uniformity in lightweight focal plane arrays. Novel techniques will be applied to solve the perceived problems associated with HgTe/CdTe SLs, namely, to achieve the activation of p-type dopants without high temperature annealing and to largely eliminate interdiffusion related problems. Commercial Applications and other Benefits as described by the awardee The technology should be immediately applicable to (1) the remote detection of WMD, particularly nuclear weapons; (2) the early detection and reliable targeting of incoming missiles under adverse conditions, such as large background clutter; (3) Air Force and Army missions requiring the sensitive, high-resolution imaging of persons and objects, often from unmanned aerial vehicles; and (4) the remote detection of chemical and biological agents for both homeland security and military use.