e-Journal of Surface Science and Nanotechnology
Online ISSN : 1348-0391
ISSN-L : 1348-0391
Conference -ICSFS-14-
Characterization of Bimetallic Au/Pd(110) Surfaces
M. MoorsT. KobielaM. KraljT. PertramC. BeckerK. Wandelt
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JOURNAL FREE ACCESS

2009 Volume 7 Pages 448-454

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Abstract

The growth as well as the compositional, electronic and structural properties of thin Au films deposited on a Pd(110) single crystal have been studied by means of ultraviolet photoelectron spectroscopy (UPS), photoemission of adsorbed xenon (PAX) and scanning tunneling microscopy (STM) as a function of film thickness (ranging from submonolayer amounts up to multilayers) and temperature. Our investigations indicate a Volmer-Weber growth mode of Au on Pd(110) at a deposition temperature of 300 K and below. As former studies already have shown, depositing Au amounts of less than 1 ML results in the formation of unreconstructed pseudomorphic Au islands. Above a critical thickness of 2 ML the formation of a (1 × 2) missing-row reconstruction typical for Au can be observed. This reconstructed Au bilayer is still in registry with Pd(110) and, thus, strained. Furthermore, our experiments show a strong temperature dependence of the surface morphology. Au multilayers prepared at 150 K, which are already quite flat, undergo a weak smoothening of the topmost atomic layer by annealing the sample up to 350 K. At a surface temperature of ∼ 450 K the diffusion of Au atoms into the bulk is initiated at the Au-Pd interface. Annealing a 3 ML thick Au film to 600 K finally results in the formation of an Au-Pd surface alloy, which is stable up to 900 K. A complete loss of Au from the surface can be detected at around 1050 K. Adsorption of CO as a probe molecule on the Au containing surfaces is only possible at low temperatures. [DOI: 10.1380/ejssnt.2009.448]

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この記事はクリエイティブ・コモンズ [表示 4.0 国際]ライセンスの下に提供されています。
https://creativecommons.org/licenses/by/4.0/deed.ja
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