论文标题
随机合金波动对（Al，GA）N量子井的电子和光学特性的影响：紧密结合计算的见解
Impact of random alloy fluctuations on the electronic and optical properties of (Al,Ga)N quantum wells: Insights from tight-binding calculations
论文作者
论文摘要
基于半导体合金铝制壳（（AL，GA）N）的光发射器近年来引起了极大的关注，因为它们在紫外线（UV）频谱窗口中的广泛应用潜力。但是，当前的最新（AL，GA）N光发射器表现出非常低的内部量子效率（IQES）。因此，了解（Al，GA）基于N的量子井的基本电子和光学特性是改善IQE的关键。在这里，我们通过经验性的原子紧密结合模型来针对C平面Al $ _x $ ga $ _ {1-x} $ n/aln量子井的电子和光学特性。特别注意随机合金波动对结果的影响以及井中的铝含量X。我们发现，在所研究的AL含量范围（从10％到75％Al）中，观察到了强孔波函数定位效应。此外，随着AL含量的增加，电子波函数也开始展示载体定位特征。总体而言，我们对C-Plane Al $ _x $ ga $ _ $ _ {1-x} $ n/aln量子井的电子结构的研究表明，已经随机合金波动足以导致（强）载体定位效应。此外，我们的结果表明，随机合金波动会影响C-Plane Al $ _x $ ga $ _ $ _ {1-x} $ n量子井中的光学极化程度。我们发现，与广泛使用的虚拟晶体近似值的结果相比，在原子计算中，从横向电气到横向磁光极化发生在原子计算中的较高含量。该观察结果对于（Al，GA）n基在深色紫外线运行的（AL，GA）的光发射二极管中的光提取效率很重要。
Light emitters based on the semiconductor alloy aluminium gallium nitride ((Al,Ga)N) have gained significant attention in recent years due to their potential for a wide range of applications in the ultraviolet (UV) spectral window. However, current state-of-the-art (Al,Ga)N light emitters exhibit very low internal quantum efficiencies (IQEs). Therefore, understanding the fundamental electronic and optical properties of (Al,Ga)N-based quantum wells is key to improving the IQE. Here, we target the electronic and optical properties of c-plane Al$_x$Ga$_{1-x}$N/AlN quantum wells by means of an empirical atomistic tight-binding model. Special attention is paid to the impact of random alloy fluctuations on the results as well as the aluminium content x in the well. We find that across the studied Al content range (from 10% to 75% Al) strong hole wave function localization effects are observed. Additionally, with increasing Al content, electron wave functions start also to exhibit carrier localization features. Overall, our investigations on the electronic structure of c-plane Al$_x$Ga$_{1-x}$N/AlN quantum wells reveal that already random alloy fluctuations are sufficient to lead to (strong) carrier localization effects. Furthermore, our results indicate that random alloy fluctuations impact the degree of optical polarization in c-plane Al$_x$Ga$_{1-x}$N quantum wells. We find that the switching from transverse electric to transverse magnetic light polarization occurs at higher Al contents in the atomistic calculation, which accounts for random alloy fluctuations, when compared to the outcome of widely used virtual crystal approximations. This observation is important for light extraction efficiencies in (Al,Ga)N-based light emitting diodes operating in the deep UV.
