Institut de Ciència de Materials de Barcelona ICMAB-CSIC, 08193 Bellaterra, Catalonia, Spain.
Small. 2010 Dec 6;6(23):2716-24. doi: 10.1002/smll.201001237.
Assembling arrays of ordered nanowires is a key objective for many of their potential applications. However, a lack of understanding and control of the nanowires' growth mechanisms limits their thorough development. In this work, an appealing new path towards self-organized epitaxial nanowire networks produced by high-throughput solution methods is reported. Two requisites are identified to generate the nanowires: a thermodynamic driving force for an unrestricted elongated equilibrium island shape, and a very fast effective coarsening rate. These requirements are met in anisotropically strained Ce(1-x)Gd(x)O(2-y) nanowires with the (011) orientation grown on the (001) surface of LaAlO(3) substrates. Nanowires with aspect ratios above ≈100 oriented along two mutually orthogonal axes are obtained leading to labyrinthine networks. A very fast effective nanowire growth rate (≈60 nm min(-1)) for ex-situ thermally annealed nanostructures derives from simultaneous kinetic processes occurring in a branched network. Ostwald ripening and anisotropic dynamic coalescence, both promoted by strain-driven attractive nanowire interaction, and rapid recrystallization, enabled by fast atomic diffusion associated with a high concentration of oxygen vacancies, contribute to such an effective growth rate. This bottom-up approach to self-organized nanowire growth has a wide potential for many materials and functionalities.
组装有序纳米线阵列是它们许多潜在应用的关键目标。然而，对纳米线生长机制的缺乏理解和控制限制了它们的深入发展。在这项工作中，报道了一种通过高通量溶液方法产生自组织外延纳米线网络的有吸引力的新途径。为了生成纳米线，确定了两个必要条件：不受限制的拉长平衡岛形状的热力学驱动力，以及非常快的有效粗化速率。这些要求在具有（011）取向的各向异性应变 Ce(1-x)Gd(x)O(2-y)纳米线中得到满足，这些纳米线在 LaAlO(3)衬底的（001）表面上生长。得到了纵横比高于 ≈100 的纳米线，它们沿着两个相互正交的轴取向，导致迷宫状网络。从外延热退火纳米结构中得到的非常快的有效纳米线生长速率（≈60nm min(-1)）源于分支网络中同时发生的动力学过程。由应变驱动的吸引力纳米线相互作用促进的奥斯特瓦尔德熟化和各向异性动态聚结，以及与高浓度氧空位相关的快速原子扩散所实现的快速再结晶，有助于实现如此高的有效生长速率。这种自下而上的自组织纳米线生长方法具有广泛的应用潜力，适用于许多材料和功能。
