多层电子叠层成像揭示的AlGaAs/GaAs量子阱中界面形貌与组分均匀性之间的权衡
Trade-off between interface morphology and compositional homogeneity in AlGaAs/GaAs quantum wells revealed by multislice electron ptychography
- University of California, Irvine（加州大学尔湾分校）
- University of Texas Austin（德克萨斯大学奥斯汀分校）
- Irvine Materials Research Institute, University of California Irvine（加州大学尔湾分校欧文材料研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过多层电子叠层成像揭示，在AlGaAs/GaAs量子阱中，尖锐平坦的界面形貌主导二次谐波响应，而生长中断在改善界面的同时加剧组分波动，为量子阱设计提供指导。
AI中文摘要：
AlGaAs/GaAs非对称耦合量子阱（ACQWs）是增强二阶光学非线性的有前景平台，其性能受到异质结构结构质量的强烈影响。平坦的界面以及高组分均匀性通常对于优化器件功能是期望的。在这里，我们表明，即使在AlGaAs层内存在显著的Al/Ga占据组分波动时，尖锐且平坦的AlGaAs/GaAs界面形貌主导了AlGaAs/GaAs ACQWs中的二次谐波产生（SHG）响应。利用多层电子叠层成像，我们在不同的生长中断条件下解析了AlGaAs/GaAs ACQWs中的三维（3D）界面形貌和组分分布。较长的生长中断使AlGaAs/GaAs界面更尖锐、更平坦，但同时导致AlGaAs层中更强的组分波动。这些发现阐明了生长中断如何调控量子阱结构，并为下一代光电器件中的量子阱设计提供了直接指导。
英文摘要：
AlGaAs/GaAs asymmetric coupled quantum wells (ACQWs) are promising platforms for enhanced second-order optical nonlinearities, with their performance strongly influenced by the structural quality of heterostructures. Flat interfaces, together with high compositional homogeneity, are generally desirable for optimizing device functionality. Here we show that sharp and flat AlGaAs/GaAs interface morphology dominates the second harmonic generation (SHG) response in AlGaAs/GaAs ACQWs, even when significant compositional fluctuations in Al/Ga occupancy are present within the AlGaAs layers. Using multislice electron ptychography, we resolve the three-dimensional (3D) interface morphology and compositional distribution in AlGaAs/GaAs ACQWs under distinct growth interruptions. Longer growth interruptions sharpen and flatten the AlGaAs/GaAs interfaces, but at the same time cause stronger compositional fluctuations in the AlGaAs layers. These findings clarify how growth interruption tunes quantum wells structures and provide direct guidance for quantum wells design in next-generation optoelectronic devices.
