Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 57: New Methods: Theory
O 57.4: Talk
Wednesday, March 20, 2024, 17:00–17:15, MA 043
Sub-nanometer depth profiling of native metal oxide layers within single fixed-angle X-ray photoelectron spectra — •Martin Wortmann1, Klaus Viertel2, Michael Westphal1, Dominik Graulich1, Yang Yang1, Maik Gärner1, Jan Schmalhorst1, Natalie Frese3, and Timo Kuschel1 — 1Bielefeld University, Bielefeld, Germany — 2Bielefeld University of Applied Sciences, Bielefeld, Germany — 3University of Hawaii, Honolulu, USA
Many metals form nanometer-thin self-passivating native oxide layers upon exposure to the atmosphere, which affect their interfacial properties and corrosion behavior. Such oxide layers are commonly analyzed by X-ray photoelectron spectroscopy (XPS). Here, we propose a simple and accessible approach for the depth profiling of ultrathin oxide layers within single fixed-angle XPS spectra. Instead of using only one peak in the spectrum, as is usually the case, we utilize all peaks within the energy range of a standard lab device, thus resembling energy-resolved XPS without the need for a synchrotron. We derived and tested new models that allow the calculation of depth-resolved concentration profiles at the oxide-metal interface, which are also valid for angular- and energy-resolved XPS. The proposed method not only improves the accuracy of earlier approaches but also paves the way for a more holistic understanding of the XPS spectrum.
Keywords: XPS; oxide; thin film; surface characterization