High Performance Dual Band Photodetector Arrays for MWIR/LWIR Imaging

Hyperspectral imaging arrays offer far more data and the ability to discriminate objects being observed. Continued difficulties with applying HgCdTe materials, especially for LWIR, present an opportunity for the development of alternate materials. One such candidate for MWIR/LWIR photodetectors are short period Type-II superlattices based on InAs/GaInSb. This material system has the ability to tune the cutoff wavelengths during device fabrication and yet be amenable to the creation of multi-spectral serially-positioned pixels. One of the issues this Phase I program will address is the intermixing of Arsenic and Antimony at the superlattice interfaces, which can hamper LWIR operation. Improved superlattice growth will be achieved through the application of newly developed MBE apparatus. At a second level, device performance will be enhanced by novel passivation of the pixel sidewalls. The Type-II superlattices with then be applied to the creation of dual-wavelength photodetectors for MWIR/LWIR imaging.