We present a detailed theoretical analysis of the electronic and optical properties of $c$-plane InGaN/GaN quantum well structures with In contents ranging from 5% to 25%. Special attention is paid to the relevance of alloy induced carrier localization effects to the green gap problem. Studying the localization length and electron-hole overlaps at low and elevated temperatures, we find alloy-induced localization effects are crucial for the accurate description of InGaN quantum wells across the range of In content studied. However, our calculations show very little change in the localization effects when moving from the blue to the green spectral regime; i.e. when the internal quantum efficiency and wall plug efficiencies reduce sharply, for instance, the in-plane carrier separation due to alloy induced localization effects change weakly. We conclude that other effects, such as increased defect densities, are more likely to be the main reason for the green gap problem. This conclusion is further supported by our finding that the electron localization length is large, when compared to that of the holes, and changes little in the In composition range of interest for the green gap problem. Thus electrons may become increasingly susceptible to an increased (point) defect density in green emitters and as a consequence the nonradiative recombination rate may increase.

中文翻译：

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极性（In，Ga）N / GaN量子阱：重新审视载流子局部化对“绿色间隙”问题的影响

我们对电子的光学特性进行了详细的理论分析 $C$In含量为5％至25％的平面InGaN / GaN量子阱结构。特别注意合金引起的载流子局部化效应与绿隙问题的相关性。研究低温和高温下的定位长度和电子-空穴重叠，我们发现合金诱导的定位效应对于在所研究的In含量范围内准确描述InGaN量子阱至关重要。但是，我们的计算表明，当从蓝色光谱变为绿色光谱时，定位效果的变化很小。也就是说，例如当内部量子效率和壁塞效率急剧下降时，由于合金引起的局部化效应而引起的面内载流子分离就会微弱地变化。我们得出结论，其他影响，例如缺陷密度增加，更有可能是造成绿色缺口问题的主要原因。我们的发现进一步支持了这一结论，即与空穴相比，电子的局域化长度很大，并且对于绿隙问题，在感兴趣的In组成范围内变化很小。因此，电子可能越来越容易受到绿色发射体中增加的（点）缺陷密度的影响，结果，非辐射复合率可能增加。