AlInGaN材料的生长及其光学性质的研究

A study of the growth and optical properties of AlInGaN alloys

研究AlInGaN材料的生长特性及其光学性质 .通过对不同生长温度生长的三个AlInGaN样品的测量 ,发现In的掺入量随着生长温度的降低而增加 ,而Al的掺入几乎没什么变化 ;在较低温度下生长的材料具有较好的材料质量与光学特性 ,其原因直接与In组分的掺入有关 ,In组分的掺入可以减少材料的缺陷 ,改善材料的质量 .同时 ,用时间分辨光谱研究了AlInGaN材料的发光机理 ,发现其发光强度随时间变化 (荧光衰退寿命 )不是指数衰减 ,而是一种伸展的指数衰减 .通过对这种伸展的指数衰减特性的研究 ,发现AlInGaN发光来自于局域激子的复合 ,且这种局域化中心呈现量子点的特性 ,延伸指数衰减行为是由不同局域态之间的局域激子的跳跃 (hopping)造成的 .此外 ,进一步研究了荧光衰退寿命随发光能量的变化关系和发光的辐射复合和非辐射复合特性 。

We have studied the growth and optical properties of AlInGaN alloys in this article. By the measurement of three samples, we found that the incorporation of In decreases with the increase of temperature, while there is nearly no change for the incorporation of Al. The sample grown at the lowest temperature had the best material and optical properties, which owes to the high In component, because the In component can reduce defects and improve the material quality. We also used the time-resolved photoluminescence(PL) to study the mechanism of recombination of carriers, and found that the time dependence of PL intensity was not in exponential decay, but in stretched-exponential decay. Through the study of the character of this decay, we come to the conclusion that the emission comes from the recombination of localized excitons. Once more, this localization exhibites the character of quantum dots, and the stretched, exponential decay results from the hopping of carriers between different localized states. In addition, we have used the relation of emission energy dependence of carrier's lifetime and the character of radiative recombination and non-radiative combination to confirm our conclusion.