Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, USA.
Nano Lett. 2010 Sep 8;10(9):3459-63. doi: 10.1021/nl1015409.
In the current examples of dislocation-driven nanowire growth, the screw dislocations that propagate one-dimensional growth originate from spontaneously formed highly defective "seed" crystals. Here we intentionally utilize screw dislocations from defect-rich gallium nitride (GaN) thin films to propagate dislocation-driven growth, demonstrating epitaxial growth of zinc oxide (ZnO) nanowires directly from aqueous solution. Atomic force microscopy confirms screw dislocations are present on the native GaN surface and ZnO nanowires grow directly from dislocation etch pits of heavily etched GaN surfaces. Furthermore, transmission electron microscopy confirms the existence of axial dislocations. Eshelby twist in the resulting ZnO nanowires was confirmed using bright-/dark-field imaging and twist contour analysis. These results further confirm the connection between dislocation source and nanowire growth. This may eventually lead to defect engineering strategies for rationally designed catalyst-free dislocation-driven nanowire growth for specific applications.
在目前的位错驱动纳米线生长实例中，传播一维生长的螺旋位错源自于自发形成的高度缺陷“种子”晶体。在这里，我们有意利用富缺陷的氮化镓 (GaN) 薄膜中的螺旋位错来传播位错驱动的生长，从而证明了氧化锌 (ZnO) 纳米线可以直接从水溶液中进行外延生长。原子力显微镜证实了螺旋位错存在于原生 GaN 表面，并且 ZnO 纳米线直接从经过重度刻蚀的 GaN 表面的位错蚀坑中生长。此外，透射电子显微镜证实了存在轴向位错。通过亮场/暗场成像和扭转轮廓分析证实了所得 ZnO 纳米线中的 Eshelby 扭转。这些结果进一步证实了位错源与纳米线生长之间的联系。这最终可能导致针对特定应用的合理设计的无催化剂位错驱动纳米线生长的缺陷工程策略。
