Physics Department, Arizona State University, Tempe, AZ 85287, USA.
Nanotechnology. 2011 Jul 29;22(30):305606. doi: 10.1088/0957-4484/22/30/305606. Epub 2011 Jul 1.
We report in situ observations of the growth of endotaxial CoSi(2) nanowires on Si(110) using an ultrahigh vacuum transmission electron microscope with a miniature electron-beam deposition system located above the pole-piece of the objective lens. Metal deposition at 750-850 °C results in formation of coherently strained silicide nanowires with a fixed length/width (L/W) aspect ratio that depends strongly on temperature. Both dimensions evolve with time as L, W ∼ t(1/3). To explain this behavior, we propose a fixed-shape growth mode based on thermally activated facet-dependent reactions. A second growth mode is also observed at 850 °C, with dimensions that evolve as L ∼ t and W ∼ constant. This mode is accompanied by formation of an array of dislocations. We expect that other endotaxial nanowire systems will follow coherently strained growth modes with similar geometrical constraints, as well as dislocated growth modes with different growth kinetics.
我们在超高真空透射电子显微镜中使用微型电子束沉积系统，在物镜的极靴上方，原位观察了 Si(110)上外延 CoSi(2)纳米线的生长。在 750-850°C 下进行金属沉积，会导致形成具有固定长度/宽度 (L/W) 纵横比的完全应变硅化物纳米线，其强烈依赖于温度。在时间的作用下，这两个维度都会发生变化，L、W∼t(1/3)。为了解释这一行为，我们提出了一种基于热激活的、依赖于晶面的反应的固定形状生长模式。在 850°C 下还观察到了第二种生长模式，其尺寸随 L∼t 和 W∼常数的变化而变化。该模式伴随着位错阵列的形成。我们预计，其他外延纳米线系统将遵循具有类似几何约束的一致应变生长模式，以及具有不同生长动力学的位错生长模式。
