The Effect of Deposition Rate on the Morphology of Fe Nanoparticles on Highly Oriented Pyrolytic Graphite, As Studied by X-ray Photoelectron Spectroscopy and Atomic Force Microscopy

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• 作者：Long Chen ; Arthur Yelon ; Edward Sacher
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：February 10, 2011
• 年：2011
• 卷：115
• 期：5
• 页码：1524-1534
• 全文大小：1338K
• 年卷期：v.115,no.5(February 10, 2011)
• ISSN：1932-7455

文摘

The effect of deposition rate on the morphology of Fe nanoparticles (NPs) on highly oriented pyrolytic graphite (HOPG) surfaces has been studied by atomic force microscopy (AFM) and in situ X-ray photoelectron spectroscopy (XPS). AFM provided the NP dimensions and the extent of surface coverage, while XPS (both core and valence levels) indicated the interaction of Fe NPs with the HOPG substrate and showed the evolutions of binding energies, full widths at half-maxima, and component peak intensity ratios, all as a function of deposition rate. The results indicate that Fe NPs react with both substrate and residual gases in the high vacuum of the instrument, forming carbide and oxide surface contaminant layers around the NPs. The NP dimensions are essentially independent of deposition rate and of the amount deposited, but the NP surface coverage is inversely related to the deposition rate, with a higher rate resulting in a lower surface coverage. Combining the NP surface coverage and the XPS peak intensity ratios, we find a relationship between deposition rate and surface contaminant layer thickness.