利用金属有机化学气相沉积(MOCVD)法在Si衬底上生长了一系列具有不同p层厚度d的InGaN/GaN蓝光LED薄膜并制备成垂直结构发光二极管(VLEDs), 研究了p层厚度即p面金属反射镜与量子阱层的间距对LED出光效率的影响, 并采用F-P干涉模型进行了理论分析。结果显示, 光提取效率受d影响很大, 随d的增加呈现类似阻尼振动的变化趋势, 分别在0.73λn处和 1.01λn处取得第一个极大值和极小值, 且前者是后者两倍多。因此优化p层厚度可以有效提高LED的出光效率。

The relationship between the thickness d of p-type GaN and light extraction efficiency of GaN based vertical light emitting diodes (VLEDs) was described in this work. The VLEDs were grown on silicon by metal organic chemical vapour deposition (MOCVD). A series of VLEDs were fabricated with varied thickness of p-type GaN. It showed that the thickness d was in the order of wavelength and it had a significant influence on extraction efficiency due to interferences. The maximum in extraction efficiency was two times more than the neighboring minimum, which were located at 0.73λn and 1.01λn, respectively. Therefore, the extraction efficiency of VLEDs can be enhanced by optimizing the thickness of p-type GaN.