In the High-power InGaN/GaN-based LED structures, p-AlGaN layer plays a role as electron blocking layer. In this paper, GaN/InGaN-based LED have been grown on sapphire by metal organic chemical vapor deposition (MOCVD), and the p-type doping mechanism and structural optimization of AlGaN layer were studied. The ways to change AlGaN components have been discussed. We found that the growth temperature, growth pressure and flow TMAl (mole ratio)have strong effect on the Al components through different mechanisms. In the AlGaN electron blocking layer, the Al composition is between 10％-30％ and the electron could be well limited to the quantum well region, maintaining a high quality crystal material. The p-type doping efficiency of AlGaN layer is low, and there is a magnesium droop problem due to lack of hole injection. A new growth method is suggestece to solve the problem. Grown under optimal conditions, the ptype AlGaN inserted in a LED structure greatly improves the output optical power of LED device.%本文利用金属有机物化学气相沉积(MOCVD)方法系统地研究了p-AlGaN层掺杂机理及优化设计生长.明确了生长温度、压力及TMAl的流量对AlGaN层Al组分的影响关系,并给出了各自不同的机理与作用.研究发现,Al组分介于10%-30%之间能够很好地将电子限定在量子阱区域并保持高的材料晶体质量.发展了一种新的生长技术来克服p-AlGaN层掺入效率低下和空穴注入不足的问题.优化条件下生长的p型AlGaN电子阻挡层很大地提升了InGaN/GaN基LED的输出光功率.
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