Technology for Producing GaAsP Transparent Photocathodes

To address the Navy need for an innovative process to fabricate gallium arsenide phosphide (GaAsP) photocathodes to improve photosensor performance parameters including wide dynamic range, uniform QE, reduced cost, and high yield, Physical Optics Corporation (POC) proposes to develop a new process for fabricating GaAsP transparent photocathodes directly on glass substrates. The process is based on new, highly efficient fabrication of GaAsP photocathode directly on an n-type silicon layer. Elimination of bonding to the glass substrate and etching of an initial wafer precludes the distortion of photocathode structure and facilitates integrity thus increasing the yield and enhancing quantum efficiency. The process offers better integrity of the photocathode structure, with reduced stress; improved dynamic range, quantum efficiency, and photocathode uniformity; and increased production yield. Photocathode produced by the new process will then be tested in an existing photodevice. In Phase I POC will demonstrate the feasibility of this innovative process and develop a detailed plan for its implementation in the fabrication of existing photodevices. In Phase II POC will conduct a detailed investigation of each production step, implement the innovative process photodevice fabrication, and demonstrate the parameters of the GaAsP photocathode in the device selected.