Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 19: Metal substrates: Adsorption of O / H and inorganic molecules II
O 19.3: Vortrag
Montag, 14. März 2011, 17:45–18:00, WIL A317
Interaction of H2O molecules with Fe films investigated with metastable induced electron spectroscopy — •Kai Volgmann1,2, Florian Voigts2, and Wolfgang Maus-Friedrichs2,3 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover — 2Institut für Physik u. Phys. Technologien, TU Clausthal, Leibnizstr. 4, 38678 Clausthal-Zellerfeld — 3Clausthaler Zentrum für Materialtechnik, TU Clausthal, Leibnizstr. 4, 38678 Clausthal-Zellerfeld
The formation of an oxide layer on Fe films upon the interaction with H2O molecules is relevant for both applications and in surface science. This work examines the interaction of H2O molecules with Fe films grown on a tungsten substrate. X-ray Photoelectron Spectroscopy is used to determine the stoichiometry of the samples, while Ultraviolet Photoelectron Spectroscopy and Metastable Induced Electron Spectroscopy (MIES) are used to analyse their valence band region and to gain information about changes in the work function because of reactions on the surface. All measurements are done at room temperature. MIES is used as a very surface sensitive technique, especially towards hydroxide groups. Only after a high H2O exposure, we observed the formation of OH groups. Our previous experiments reveal that a passivating oxide layer is formed during oxygen offer to a Fe surface [1]. A similar oxide layer growth may be observed during H2O offer to iron. This oxide layer forms prior to the development of any observable OH groups. [1] K.Volgmann, F. Voigts, W. Maus-Friedrichs, Surface Science, 604 (2010), 906-913