The nature of carrier localisation in polar and nonpolar InGaN/GaN quantum wells
The nature of carrier localisation in polar and nonpolar InGaN/GaN quantum wells
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DOI：
10.1063/1.4948237
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发表时间：
2016-05-14
影响因子：
3.2
通讯作者：
Humphreys, C. J.
中科院分区：
文献类型：
--
作者：
Dawson, P.;Schulz, S.;Humphreys, C. J.
本文对极性和非极性InGaN/GaN量子阱结构的低温光学性质的实验数据和理论预测进行了比较。在这两种类型的结构中，低温下的光学性质都受到载流子局域化效应的影响。在极性结构中，内置电场的作用导致电子主要局限于阱宽波动处，而空穴局限于量子威尔斯内的区域，其中随机In分布导致势能的局部最小值。这导致了一个独立的局域电子和空穴系统。在非极性量子威尔斯阱中，空穴局域化的性质基本上与极性情况相同，但是电子现在被库仑束缚到空穴上，形成局域激子。这些本地化机制是兼容的极性和非极性量子威尔斯以及不同的时间尺度和形式的辐射复合衰减曲线的大的光致发光线宽。(C)2016年作者。
In this paper, we compare and contrast the experimental data and the theoretical predictions of the low temperature optical properties of polar and nonpolar InGaN/GaN quantum well structures. In both types of structure, the optical properties at low temperatures are governed by the effects of carrier localisation. In polar structures, the effect of the in-built electric field leads to electrons being mainly localised at well width fluctuations, whereas holes are localised at regions within the quantum wells, where the random In distribution leads to local minima in potential energy. This leads to a system of independently localised electrons and holes. In nonpolar quantum wells, the nature of the hole localisation is essentially the same as the polar case but the electrons are now coulombically bound to the holes forming localised excitons. These localisation mechanisms are compatible with the large photoluminescence linewidths of the polar and nonpolar quantum wells as well as the different time scales and form of the radiative recombination decay curves. (C) 2016 Author(s).