Silver on Pt(100) - room temperature growth and high temperature alloying
Silver on Pt(100) - room temperature growth and high temperature alloying
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DOI：
10.1016/j.susc.2003.12.023
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发表时间：
2004-03-20
期刊：
影响因子：
1.9
通讯作者：
Koel, BE
中科院分区：
文献类型：
--
作者：
Batzill, M;Koel, BE
用扫描隧道显微镜(STM)和俄歇电子能谱(AES)初步研究了300K下重建的铂(100)表面亚单层到单层银膜的生长及其结构随温度的变化。在300K时，观察到了由Ag80Pt20组成的细长2D-AD岛的形成。这一岛状化学计量比取决于由于生长的Ag岛移除干净的铂(100)表面的六角重建而排出的铂量。岛的形状可以通过重建的各向异性稳定性来解释，重建的行图案用作岛生长的模板。600 K以上的退火可导致更广泛的合金化，从Ag-PT交换开始，并在表层形成纳米相的Ag-PT合金。有了足够的银，这种合金就会在整个表面上扩散，直到在整个表面上建立统一的化学计量比。依赖温度的俄歇电子能谱研究表明，在高温下，银与块体铂发生了一定程度的混合。(C)2003爱思唯尔B.V.保留所有权利。
Growth of submonolayer to monolayer silver films on the reconstructed Pt(100) surface at 300 K and evolution of the structure with increasing temperature was studied primarily by scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). At 300 K, formation of elongated 2D-adislands with a composition of Ag80Pt20 was observed. This island stoichiometry is dictated by the amount of Pt expelled due to removal of the hex-reconstruction of the clean Pt(100) surface by the growing Ag adislands. The island shape can be explained by an anisotropic stability of the reconstruction, with the row pattern of the reconstruction acting as a template for island growth. Annealing of the sample above 600 K causes more extensive alloying starting at the perimeter of the Ag adislands by Ag-Pt exchange and formation of a nanophasic Ag-Pt alloy confined to the surface layer. With sufficient Ag, this alloy spreads across the surface until a uniform stoichiometry is established over the entire surface. Temperature-dependent AES studies indicate that there is some mixing of Ag with bulk Pt at elevated temperatures. (C) 2003 Elsevier B.V. All rights reserved.