Guided growth of horizontal ZnO nanowires with controlled orientations on flat and faceted sapphire surfaces.
Guided growth of horizontal ZnO nanowires with controlled orientations on flat and faceted sapphire surfaces.
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DOI：
10.1021/nn3020695
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发表时间：
2012-07
期刊：
影响因子：
17.1
通讯作者：
David Tsivion;M. Schvartzman;R. Popovitz‐Biro;E. Joselevich
中科院分区：
文献类型：
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作者：
David Tsivion;M. Schvartzman;R. Popovitz‐Biro;E. Joselevich
由于在表面上可控地组装这些纳米级物体的能力有限，纳米线大规模集成到实际设备中的能力受到阻碍。在我们首次报道了具有可控取向的毫米长水平纳米线的引导生长之后，我们在这里通过将引导生长方法从GaN纳米线扩展到氧化锌纳米线来演示其一般性。我们描述了在蓝宝石的八个不同平面(包括平面和刻面)上水平定向生长晶向可控的氧化锌纳米线。纳米线的生长方向、晶体取向和刻面对于每个表面平面都是恒定的，由它们与衬底的外延关系以及引导它们沿表面台阶和沟槽生长的梯度外延效应决定。这些水平的氧化锌纳米线表现出与垂直生长的纳米线相当的光学和电学性能，表明缺陷的浓度很低。虽然这里描述的氧化锌纳米线的引导生长在总体上与GaN纳米线的引导生长相似，但它也显示出显著的不同和定性的新现象，例如纳米线的控制生长具有邻近取向、纵向晶界和厚度相关的取向。这篇文章证明了引导生长现象的普遍性，它使我们能够创造出具有其他方法无法获得的潜在应用的高度可控的纳米线结构和阵列。
The large-scale integration of nanowires into practical devices is hindered by the limited ability to controllably assemble these nanoscale objects on surfaces. Following our first report on the guided growth of millimeter-long horizontal nanowires with controlled orientations, here we demonstrate the generality of the guided growth approach by extending it from GaN nanowires to ZnO nanowires. We describe the guided growth of horizontally aligned ZnO nanowires with controlled crystallographic orientations on eight different planes of sapphire, including both flat and faceted surfaces. The growth directions, crystallographic orientation, and faceting of the nanowires are constant for each surface plane and are determined by their epitaxial relation with the substrate, as well as by a graphoepitaxial effect that guides their growth along surface steps and grooves. These horizontal ZnO nanowires exhibit optical and electronic properties comparable to those of vertically grown nanowires, indicating a low concentration of defects. While the guided growth of ZnO nanowires described here resembles the guided growth of GaN nanowires in its general aspects, it also displays notable differences and qualitatively new phenomena, such as the controlled growth of nanowires with vicinal orientations, longitudinal grain boundaries, and thickness-dependent orientations. This article proves the generality of the guided growth phenomenon, which enables us to create highly controlled nanowire structures and arrays with potential applications not available by other means.