Effect of surrounding environment on atomic structure and equilibrium shape of growing nanocrystals: gold in/on SiO2
Effect of surrounding environment on atomic structure and equilibrium shape of growing nanocrystals: gold in/on SiO2
复制标题
周围环境对生长纳米晶体的原子结构和平衡形状的影响：SiO2 中/上的金
DOI：
--
复制
发表时间：
2007
影响因子：
--
通讯作者：
M. Grimaldi
中科院分区：
文献类型：
--
作者：
F. Ruffino;C. Bongiorno;F. Giannazzo;F. Roccaforte;V. Raineri;M. Grimaldi
我们报告的平衡形状和原子结构的热处理Au纳米晶体（NC）的高分辨率透射电子显微镜（TEM）确定。纳米碳沉积在SiO2表面或嵌入SiO2层中。通过逆Wulff构造获得了关于NC表面自由能的定量数据。SiO2层内的纳米晶是无缺陷的，并在生长过程中保持对称的平衡形状。SiO2表面的纳米晶表现出不对称的平衡形状，其特征在于通过引入孪晶和更复杂的原子缺陷超过临界尺寸。观察到的平衡形状和原子结构演变的纳米碳和SiO2上的解释在各向同性/各向异性的环境中的演变，使表面自由能函数角和/或径向对称/不对称的旋转/平移不变性的表面应力张量。
We report on the equilibrium shape and atomic structure of thermally-processed Au nanocrystals (NCs) as determined by high resolution transmission electron microscopy (TEM). The NCs were either deposited on SiO2surface or embedded in SiO2layer. Quantitative data on the NCs surface free energy were obtained via the inverse Wulff construction. Nanocrystals inside the SiO2layer are defect-free and maintain a symmetrical equilibrium shape during the growth. Nanocrystals on SiO2surface exhibit asymmetrical equilibrium shape that is characterized by the introduction of twins and more complex atomic defects above a critical size. The observed differences in the equilibrium shape and atomic structure evolution of growing NCs in and on SiO2is explained in terms of evolution in isotropic/anisotropic environment making the surface free energy function angular and/or radial symmetric/asymmetric affecting the rotational/translational invariance of the surface stress tensor.