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O: Oberflächenphysik
O 23: Oberfl
ächenreaktionen II
O 23.3: Talk
Tuesday, March 25, 2003, 15:30–15:45, M\"UL/ELCH
Chemicurrent measurements during oxidation of Mg surfaces — •Hermann Nienhaus1 and Stefan Glass2 — 1Experimentalphysik, Universität Essen — 2Festkörperphysik, Universität Duisburg
The reaction of oxygen molecules with thin Mg films is studied by chemicurrent measurements and Auger electron spectroscopy (AES). The chemicurrent is due to non-adiabatic processes during the reaction and is detected with Mg/p-Si(111) Schottky diodes. Together with AES results, the oxygen coverage is found to be proportional to the detected charge in the diode. First, the chemicurrent increases with oxygen exposure, reaches a maximum value and, eventually, decreases for longer exposure times. This chemicurrent transient is solely related to variations of the sticking probability of oxygen on Mg surfaces.