Growth of p-GaN at low temperature and its properties as light emitting diodes

The p-type GaN(p-GaN) samples grown at low temperature 870-980 degrees C on sapphire substrate were prepared by the metal organic chemical vapor deposition technique(MOCVD), and their electrical properties were investigated. The p-GaN samples grown below 900 degrees C show high-resistivity, and samples grown at above 900 degrees C have good conductivity. In addition, the electrical properties are also related with the doping level and the growth condition of p-GaN. The low N-Ga mole ratio leads to poor conductivity, the high ratio leads to rough morphology. At last, we use the optimized p-GaN to fabricate the green-light emitting diodes. We found that when the growth temperature is lower, the luminescence intensity and reverse voltage is higher but the forward voltage increases slightly.