Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014)
    Thin Films Wednesday Sessions
       Session TF-WeM

Paper TF-WeM1
Novel Methods for Fitting the Fe 2p and Sn 3d XPS Data from Metallic and Oxidized Surfaces

Wednesday, December 10, 2014, 8:00 am, Room Makai

Session: Thin Film Synthesis and Characterization II
Presenter: Jorge A. Huerta-Ruelas, CICATA-Queretaro, Mexico
Authors: M. Bravo-Sanchez, CINVESTAV-Unidad Queretaro, Mexico
J.A. Huerta-Ruelas, CICATA-Queretaro, Mexico
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Fe and Sn oxides are present in many products and industrial processes. Surface analysis with techniques such as X-ray photoelectron spectroscopy (XPS) plays a crucial role in understanding their properties. Most of the core level spectra from metallic and oxidized Fe and Sn surfaces show very large background signals, highly asymmetrical line-shapes, and a series of shake-up satellites that overlaps with the higher binding-energy branch of the peak doublets. For these reason, a proper fit of these spectra has been elusive. This has prevented the quantification, through the analysis of XPS data, of the composition of oxidized surfaces and of the thickness of thin oxide layers. In this work we jointly employed the SVSC background [1] and the double Lorentzian line-shape [2] to closely model the Fe 2p and Sn 3d spectra. With this approach it was possible to resolve previously unreported shake-up satellites and to quantify the thickness and composition of thin oxide films. The validity of the method is strongly suggested from the reproduction of the thickness assessed with transmission electron microscopy. The expected compositions are also reproduced. Examples of oxide films ranging from 2 to 5 nm will be discussed in full. [1] A. Herrera-Gomez, M. Bravo-Sanchez, O. Ceballos-Sanchez, and M.O. Vazquez-Lepe. Journal of Electron Spectroscopy and Related Phenomena (in press) DOI 10.1002/sia.5453. [2] A. Herrera-Gomez. “A double Lorentzian shape for asymmetric photoelectron peaks.” Internal Report. Cinvestav-Querétaro.(2011). http://www.qro.cinvestav.mx/~aherrera/reportesInternos/doubleLorentzian.pdf