Self-assembled GaN quantum wires on GaN/AlN nanowire templates
Self-assembled GaN quantum wires on GaN/AlN nanowire templates
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DOI：
10.1039/c2nr32173d
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发表时间：
2012-01-01
期刊：
影响因子：
6.7
通讯作者：
Eickhoff, Martin
中科院分区：
文献类型：
--
作者：
Arbiol, Jordi;Magen, Cesar;Eickhoff, Martin
提出了一种新的GaN量子线(QWR)自组装生长方法，该方法在两个空间维度上表现出较强的限制效应。以AlN/GaN纳米线为模板，在AlN/GaN纳米线的六个交叉点上形成的{11(2)面上选择性成核形成了GaN量子线。在显微镜观察的基础上，我们建立了一个三维模型来解释QWR的生长机制。我们证明了量子线的形成是由纳米线(NWS)侧面上的自限伪态生长控制的。通过观察到发射能量高达4.4 eV的单个QWR产生的窄的光致发光线，证实了QWR中的量子受限。时间分辨光致发光研究表明QWR发射的衰减时间很短(类似于120ps)。用氮化铝覆盖QWR可以增强由于压缩应变引起的蓝移的光致发光。单量子阱的发射能量被模拟为一个三角形截面，这是由a面上的自限生长引起的。与实验结果比较，得到了平均直径约为2.7 nm的QWR，与结构特征一致。这些结果为一维半导体量子结构的可控实现开辟了一条新的途径，不仅在基础研究方面具有很高的潜力，而且在电子学和紫外光产生方面也有应用。
We present a novel approach for self-assembled growth of GaN quantum wires (QWRs) exhibiting strong confinement in two spatial dimensions. The GaN QWRs are formed by selective nucleation on {11 (2) over bar0} (a-plane) facets formed at the six intersections of {1 (1) over bar 00} (m-plane) sidewalls of AlN/GaN nanowires used as a template. Based on microscopy observations we have developed a 3D model explaining the growth mechanism of QWRs. We show that the QWR formation is governed by self-limited pseudomorphic growth on the side facets of the nanowires (NWs). Quantum confinement in the QWRs is confirmed by the observation of narrow photoluminescence lines originating from individual QWRs with emission energies up to 4.4 eV. Time-resolved photoluminescence studies reveal a short decay time (similar to 120 ps) of the QWR emission. Capping of the QWRs with AlN allows enhancement of the photoluminescence, which is blue-shifted due to compressive strain. The emission energies from single QWRs are modelled assuming a triangular cross-section resulting from self-limited growth on a-plane facets. Comparison with the experimental results yields an average QWR diameter of about 2.7 nm in agreement with structural characterization. The presented results open a new route towards controlled realization of one-dimensional semiconductor quantum structures with a high potential both for fundamental studies and for applications in electronics and in UV light generation.