Extremely low Power on Focal Plane Digital Conversion

Not Available It is clear that only large bulk single crystals of gallium nitride can alleviate the electrical and optical problems that plague present gallium nitride thin films grown on unmatched sapphire substrates. Therefore we propose to produce large bulk single crystals of gallium nitride by starting with perfectly lattice-matched LiGaO2 substrates and utilizing the rapid growth rated affordable by halide vapor phase epitaxy (HVPE). Anticipated growth rates will be 50 to 100 microns per hour. First a thin buffer layer of GaN will be grown by MOCVD on the new LiGaO2 substrates to guard against corrosion by HC1. Our new hybrid MOCVD/HVPE reactor will allow all processing to be performed in on cycle. The oxide substrates will subsequently be removed by wet chemical etching, leaving large area free standing wafers of gallium nitride. Such wafers will be made available commercially by Crystal Photonics Inc for homoepitaxial growth of gallium nitride films. With a conducting substrate, present device contacting problems will be eliminated. Very low defect densities will induce high power densities in blue diode lasers. In Phase I, we shall prepare blue GaN light-emitting diodes on our new wafers to demonstrate their utility. Lasers will be produced during Phase II