Advanced Fullerene Thermal Protection for Exterior Aircraft Structures

Not Available Photodetectors operating at 8-15 mm and beyond are of great importance for commercial and military applications in infrared (IR) thermal imaging. InAs/InGaSb type-II quantum wells (QWs) have advantages over HgCdTe for applications requiring higher temperature and longer wavelength operation. The type-II QW photodiodes would have comparable quantum efficiency and smaller dark current due to a larger effective mass, and enhanced lifetimes due to much slower Auger recombination rates, and hence much longer carrier lifetime. Through careful bandgap engineering, we have suppressed the Auger coefficient by a factor > 8 for 4.5-mm type-II QW mid-IR lasers at 300 K. With improved MBE growth technology, we have improved the responsivity of type-II photoconductors by a factor 50, due to the improved interface quality. Currently, we have demonstrated among the best performance of photoconductors using III-V materials up to 14 mm. Recently, we have demonstrated a four times better photoresponse of 13 mm photoconductor from InAs/InGaSb superlattice layers grown on GaAs compliant substrate compared to that on GaSb substrate. In this program, we will develop both the growth of large two-dimensional arrays of IR photodetectors based on InAs/InGaSb type-II QWs at 8 to 15 mm and 2 inch GaAs universal compliant substrate technology.