Functionalization of Droplet Etching for Quantum Rings
Functionalization of Droplet Etching for Quantum Rings
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DOI：
10.1007/978-3-319-95159-1_6
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
C. Heyn;M. Zocher;W. Hansen
中科院分区：
文献类型：
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作者：
C. Heyn;M. Zocher;W. Hansen
我们给出了一个概述各种类型的应变无半导体量子环（QR）结构中创建的自组装的方式与本地液滴蚀刻（LDE）方法。LDE与传统的分子束外延（MBE）完全兼容，并利用在半导体表面钻纳米孔的液体Ga或Al液滴。纳米孔开口被由液滴材料的砷化物组成的壁包围。在这里，纳米孔和壁的形成机制和它们的结构特性的可调谐性进行了讨论。三个不同的概念QR生成LDE解决。在第一个概念中，GaAs在LDE过程中与AlGaAs衬底上的Ga液滴再结晶，直接形成GaAs量子环。第二个概念是基于V形GaAs量子点的波函数调谐通过施加的栅极电压。在这里，电子或空穴波函数可以变换成环形，而相应的其他电荷载流子类型保持在零维QD状态。第三个概念考虑了近表面GaAs量子阱（QW）由于隧穿的部分耗尽。LDE相关的壁局部地增加了到表面的距离，这减少了隧穿并在壁下方的QW中产生环形电荷载流子浓度。这三种类型的QR的制造和结构特性，量子化的电子能级和波函数的模拟，和第一光学数据进行了讨论。
We give an overview on various types of strain-free semiconductor quantum ring (QR) structures created in a self-assembled fashion with the local droplet etching (LDE) method. LDE is fully compatible with conventional molecular beam epitaxy (MBE) and utilizes liquid Ga or Al droplets which drill nanoholes into semiconductor surfaces. The nanohole openings are surrounded by walls composed of Arsenides of the droplet material. Here the nanohole and wall formation mechanisms and the tunability of their structural properties are discussed. Three different concepts for QR generation by LDE are addressed. In the first concept, GaAs recrystallized during LDE with Ga droplets on AlGaAs substrates forms directly GaAs quantum rings. The second concept is based on the wave-function tuning of V-shaped GaAs QDs by an applied gate-voltage. Here, either the electron or the hole wave function can be transformed into a ring-shape, whereas the respective other charge carrier type remains in a zero-dimensional QD state. The third concept considers the partial depletion of a near surface GaAs quantum well (QW) due to tunneling. The LDE-related wall increases locally the distance to the surface which reduces tunneling and generates a ring-shaped charge-carrier concentration in the QW below the wall. The fabrication and structural properties of these three types of QRs, simulations of the quantized electronic levels and wave functions, and first optical data are discussed.