Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
J Phys Chem A. 2011 Jun 30;115(25):7096-104. doi: 10.1021/jp1124266. Epub 2011 Jun 9.
High resolution spot profile analysis low energy electron diffraction (SPA-LEED) and variable temperature scanning tunneling microscopy (STM) have been used to observe the growth of Pb on the Pb/Si(111)-α√3×√3 phase, which is driven by quantum size effects (QSE). A change in the rotation of the Pb grown islands with respect to the Si substrate has been observed with increasing coverage θ. At lower coverage, separated two-step islands are grown and are aligned with the [110] axis of the substrate. With increasing coverage above 1.5 ML, of the islands coalesce and form a bilayer, with additional islands grown on top. The preferred Pb island orientation changes to 5.6° with respect to the [110] direction. These changes at the metal/semiconductor buried interface are obtained both with SPA LEED and STM as changes to the period of the Moire pattern. The method of analysis of the corrugation period and rotation angle of the Moire pattern measured with diffraction and STM can be applied to obtain the structure of buried metal/substrate interfaces in other epitaxial systems.
高分辨率斑点轮廓分析低能电子衍射 (SPA-LEED) 和变温扫描隧道显微镜 (STM) 已被用于观察由量子尺寸效应 (QSE) 驱动的 Pb 在 Pb/Si(111)-α√3×√3 相上的生长。随着覆盖度θ的增加，观察到 Pb 生长岛相对于 Si 衬底的旋转发生了变化。在较低的覆盖度下，生长的分离两步岛与衬底的[110]轴对齐。随着覆盖度超过 1.5 ML，岛开始合并形成双层，并且在顶部生长了额外的岛。与[110]方向相比，Pb 岛的优选取向变化为 5.6°。这些在金属/半导体埋层界面处的变化可以通过 SPA LEED 和 STM 获得，因为莫尔图案的周期发生了变化。通过衍射和 STM 测量的莫尔图案的波纹周期和旋转角的分析方法可应用于获得其他外延系统中埋置金属/衬底界面的结构。
