p型氮化镓的低温生长及发光二极管器件的研究

采用金属有机物化学气相淀积技术(MOCVD)在蓝宝石衬底上低温(870—980℃)生长p型氮化镓 (p-GaN).用Hall测试仪测量材料的电学性能，发现当温度低于900℃时，材料的电阻率较高 ；在900—980℃均可获得导电性能良好的p-GaN.另外，电导性能除与掺杂浓度有关，还与p- GaN生长条件有关，氮镓摩尔比过低导电性能就较差，过高则会引起表面粗糙.采用优化后的 p-GaN制作了绿光发光二极管器件，发现生长温度越低器件发光强度越高，反向电压也越高 ，但正向电压只是略有升高. 关键词： Ⅲ-Ⅴ族半导体 氮化镓 发光二极管 金属有机物化学气相淀积

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℃ on sapphire su bstrate were prepared by the metal organic chemical vapor deposition technique(M OCVD), and their electrical properties were investigated. The p-GaN samples grow n below 900℃ show high-resistivity, and samples grown at above 900℃ have good conductivity. In addition, the electrical properties are also related with the d oping 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.