AlInGaN合金的发光机制研究

Luminescence Mechanism Studies of AlInGaN Alloy

用变温光致发光谱和时间分辨光谱研究了AIlnGaN合金的发光机制。实验结果表明,发光强度随时间并不是呈指数衰减关系,而可以用伸展指数哀减函数来描述,表明材料中存在明显的无序。形成这种无序的原因是In组分不均产生的微结构(如量子点)。伸展指数衰减函数中弥散指数β不仅不随温度变化,在250K也不随辐射能量变化,表明载流子的弥散过程由局域态之间的跳跃所主导。进一步实验表明局域态在250K时仍然表现出零维特性。

The luminescence mechanism of AlInGaN alloy was studied by temperature-dependent photoluminescence spectroscopy and time-resolved photoluminescence (TRPL) spectroscopy. The TRPL signals exhibit nonexponential decay behavior and could be expressed as a stretched exponential decay, indicating significant disorder in the material. We attribute this disorder to nanoscale structures(such as quantum dots) caused by indium fluctuations. The dispersive exponent β is not only independent of temperature , but also independent of emission energy at 250K, which indicates that the stretched exponential kinetics results from hopping of carriers among localized states. Further study shows that the dimension of DOS for localized states remains zero until 250K.