Sensor Electronic Technology, Inc. (SET) proposes to develop ultraviolet detectors for focal plane arrays based on wide-bandgap semiconductor materials. Direct gap III?N AlInGaN materials are the only materials capable of combining a high sensitivity for detecting UV radiation with a sharp cutoff for either visible blind (cutoff < 400 nm) or solar-blind (cutoff < 290 nm) operation. These solid state detectors are rugged, suitable in high temperature applications, have fast response times, and have spatial resolution when integrated with a silicon readout integrated circuit (ROIC). This Phase I effort will focus on the feasibility for fabricating high quantum efficiency UV detectors with the possibility to integrate multi-wavelength detection onto a single pixel. This will include heterojunction optimization that will be applicable for both single color and multi-color UV detectors. SET will perform MEMOCVD growth of high Al containing heterojunctions and will investigate the influence of material properties such as doping efficiency, donor and acceptor compensation, dopant diffusion and profile, and adatom surface migration and their influence on heterojunction performance in advanced UV photodetectors.