Initial Oxidation of Cu(hkl) Surfaces Vicinal to Cu(111): A High-Throughput Study of Structure Sensitivity
Initial Oxidation of Cu(hkl) Surfaces Vicinal to Cu(111): A High-Throughput Study of Structure Sensitivity
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DOI：
10.1021/jp303488t
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发表时间：
2012-08-02
影响因子：
3.7
通讯作者：
Gellman, A. J.
中科院分区：
文献类型：
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作者：
Lawton, T. J.;Pushkarev, V.;Gellman, A. J.
在表面结构扩展单晶（（SC）-C-4）上研究了Cu单晶表面氧化的初始阶段，暴露出位于（111）平面的10度极角内的所有Cu（hkl）表面取向的连续分布，Cu（111）+/-10度-（SC）-C-4。利用空间分辨X射线光电子能谱（XPS）测量了在300 K下暴露于O-2期间Cu（111）+/-10度-（SC）-C-4上的氧吸收，并利用扫描隧道显微镜（STM）对所得Cu 2 O表面氧化物层进行了成像。氧的吸收取决于表面台阶密度，并且随着相对于（111）极的极角的增加而增加。相反，氧吸收不依赖于台阶边缘的晶体学取向，或者换句话说，不依赖于沿台阶边缘沿着的扭结密度。STM图像显示，一旦台阶边缘的氧化开始，Cu 2 O台阶氧化物层的所有边界都沿着Cu（111）平台中的（100）台阶边缘取向，而与台阶的初始取向无关。换句话说，氧化台阶边缘不具有其原始取向的记忆，因此，台阶生长仅取决于台阶密度，而不取决于沿着台阶边缘的扭结密度。结合使用空间分辨XPS和STM的原子尺度成像在Cu（111）+/- 10度-（SC）-C-4上提供了对结构敏感的表面化学的起源的独特见解。
The initial stage in the oxidation of Cu single crystal surfaces has been studied on a surface structure spread single crystal ((SC)-C-4) exposing a continuous distribution of all Cu(hkl) surface orientations lying within 10 degrees polar angle of the (111) plane, Cu(111)+/- 10 degrees-(SC)-C-4. The uptake of oxygen across the Cu(111) +/- 10 degrees-(SC)-C-4 during exposure to O-2 at 300 K has been measured using spatially resolved X-ray photoelectron spectroscopy (XPS), and the resulting Cu2O surface oxide layer has been imaged using scanning tunneling microscopy (STM). Uptake of oxygen is dependent on surface step density and increases with increasing polar angle relative to the (111) pole. In contrast, the oxygen uptake does not depend on the crystallographic orientation of the step edge or, in other words, the kink density along the step edge. STM images reveal that once oxidation of the step edges begins, all of the boundaries of the Cu2O step oxide layer are oriented along (100) step edges in the Cu(111) terrace independent of the initial orientation of the step. In other words, the oxidizing step edges have no memory of their original orientation, and thus, the step growth depends only on step density and not on the kink density along the step edge. The combined use of both spatially resolved XPS and atomic scale imaging with STM on a Cu(111) +/- 10 degrees-(SC)-C-4 has provided unique insight into the origins of structure-sensitive surface chemistry.