Sonner Maximilian M, Sitek Anna, Janker Lisa, Rudolph Daniel, Ruhstorfer Daniel, Döblinger Markus, Manolescu Andrei, Abstreiter Gerhard, Finley Jonathan J, Wixforth Achim, Koblmüller Gregor, Krenner Hubert J
Lehrstuhl für Experimentalphysik 1, Institut für Physik and Augsburg Centre for Innovative Technologies (ACIT) , Universität Augsburg , Universitätsstr. 1 , 86159 Augsburg , Germany.
Nanosystems Initiative Munich (NIM) , Schellingstr. 4 , 80799 München , Germany.
Nano Lett. 2019 May 8;19(5):3336-3343. doi: 10.1021/acs.nanolett.9b01028. Epub 2019 Apr 30.
We report a comprehensive study of the impact of the structural properties in radial GaAs-AlGaAs nanowire-quantum well heterostructures on the optical recombination dynamics and electrical transport properties, emphasizing particularly the role of the commonly observed variations of the quantum well thickness at different facets. Typical thickness fluctuations of the radial quantum well observed by transmission electron microscopy lead to pronounced localization. Our optical data exhibit clear spectral shifts and a multipeak structure of the emission for such asymmetric ring structures resulting from spatially separated, yet interconnected quantum well systems. Charge carrier dynamics induced by a surface acoustic wave are resolved and prove efficient carrier exchange on native, subnanosecond time scales within the heterostructure. Experimental findings are corroborated by theoretical modeling, which unambiguously show that electrons and holes localize on facets where the quantum well is the thickest and that even minute deviations of the perfect hexagonal shape strongly perturb the commonly assumed 6-fold symmetric ground state.
我们报告了一项关于径向GaAs-AlGaAs纳米线量子阱异质结构的结构特性对光复合动力学和电输运特性影响的综合研究，特别强调了在不同晶面处量子阱厚度常见变化所起的作用。通过透射电子显微镜观察到的径向量子阱典型厚度波动会导致明显的局域化。我们的光学数据显示，对于这种由空间分离但相互连接的量子阱系统产生的不对称环形结构，发射光谱有明显的光谱位移和多峰结构。由表面声波引起的电荷载流子动力学得到了解析，并证明在异质结构内的纳秒级时间尺度上，原生载流子能进行有效的交换。理论建模证实了实验结果，该模型明确表明电子和空穴会局域在量子阱最厚的晶面上，并且即使是完美六边形形状的微小偏差也会强烈扰动通常假定的六重对称基态。
