Effects of alloy potential fluctuations in InGaN epitaxial films
Effects of alloy potential fluctuations in InGaN epitaxial films
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DOI：
10.1088/0268-1242/14/5/006
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发表时间：
1999-05
影响因子：
1.9
通讯作者：
Tai-Yuan Lin;J. Fan;Yanguang Chen
中科院分区：
文献类型：
--
作者：
Tai-Yuan Lin;J. Fan;Yanguang Chen
给出了外延薄膜的光致发光和光电导测量结果。光致发光峰的能量和强度表现出几种反常的行为。峰值能量随温度的变化呈现出倒S形的依赖性，在40-100 K的范围内，它降低，然后随着温度的升高而增加，最后随着温度的升高而降低。强度显示出类似于非晶半导体和无序超晶格的温度依赖性。随着激发强度的增加，观察到的光致发光能量的蓝移。发现光致发光峰位和带边跃迁能量之间存在较大的斯托克斯位移，且随着铟含量的降低而减小。一个持久的光电导效应已被检测到室温与拉伸指数函数的衰减率。所有这些观察结果都可以用合金电位波动来解释，这清楚地表明了成分波动的存在。因此，这两个相关的影响似乎构成了广泛观察到的局域激子在InGaN基器件的机制。
Results of photoluminescence and photoconductivity measurements in epitaxial films are presented. The photoluminescence peak energy and intensity show several anomalous behaviours. The peak energy changes with temperature exhibiting an inverted S-shape dependence, where it decreases, then increases with increasing temperature in the range 40-100 K and finally decreases with increasing temperature. The intensity shows a temperature dependence similar to that of amorphous semiconductors and disordered superlattices. A blue shift of the photoluminescence energy with increasing excitation intensity is observed. A large Stokes shift between the photoluminescence peak position and the band edge transition energy is found; it decreases with decreasing indium content. A persistent photoconductivity effect has been detected up to room temperature with a stretched-exponential function for its decay rate. All these observations can be explained in a consistent way by alloy potential fluctuations, and these clearly indicate the existence of compositional fluctuations. These two related effects thus appear to constitute the mechanism for the widely observed localized excitons in InGaN-based devices.