基于蓝宝石纳米图形衬底上氮化镓生长的研究

利用两步生长法在蓝宝石纳米图形衬底（NPSS）上生长得到高质量的氮化镓薄膜。通过XRD和SEM对薄膜质量的表征和研究发现，为得到高质量的氮化镓（GaN）薄膜，在NPSS上生长时得到的最优缓冲层厚度为15nm，而在微米级尺寸的图形衬底（MPSS）上得到的最优缓冲层厚度远大于15nm。同时，在NPSS上生长氮化镓薄膜的过程中观察到一个有趣的现象，即GaN在NPSS上生长的初始阶段，氮化镓晶粒主要在图形之间的平面区域生长，极少量的GaN在衬底图形的侧面上聚集生长。这一有趣的现象明显不同于GaN在MPSS上的生长过程。接着，又在NPSS上生长了GaN基LED结构，并对其光电性能进行了研究。

GaN grown on nano-patterned sapphire substrates

High-quality gallium nitride (GaN) film was grown on nano-patterned sapphire substrates (NPSS) and investigated using XRD and SEM. It was found that the optimum thickness of the GaN buffer layer on the NPSS is 15 nm, which is thinner than that on micro-patterned sapphire substrates (MPSS). An interesting phenomenon was observed for GaN film grown on NPSS:GaN mainly grows on the trench regions and little grows on the sidewalls of the patterns at the initial growth stage, which is dramatically different from GaN grown on MPSS. In addition, the electrical and optical properties of LEDs grown on NPSS were characterized.