Epitaxial gallium phosphide (GaP) will be studied as a promising new material for the manufacture of particle detectors. Due to a high indirect bandgap and exceptional crystalline quality, epitaxial gallium phosphide detectors will provide superior performance in high-temperature, high- radiation environments. Extremely low reverse saturation current and good signal-to-noise ratios are expected from gallium phosphide detectors. This Phase I program will apply a systematic approach to demonstrate the capabilities of epitaxial GaP detectors. A comprehensive study of intrinsic and compensated high resistivity epitaxial gallium phosphide layers and PN detectors will be performed. A novel device design intended to extend the high energy collection efficiency of an epitaxial particle detector will be proven. The Phase II program will further develop and optimize this device as well as develop a technology to economically produce millimeter thick epitaxial layers of high resistivity detector grade gallium phosphide.
