SKM 2023 – scientific programme

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O: Fachverband Oberflächenphysik

O 23: Poster: Surface Reactions

O 23.6: Poster

Monday, March 27, 2023, 18:00–20:00, P2/EG

Chemicurrent measurements during oxidation of Mg films with varying impact energy — •Tobias Prost and Hermann Nienhaus — Fakultät für Physik, Universität Duisburg-Essen, Germany

The chemicurrent originating from the oxidation of super thin magnesium films in correlation with the kinetic energies of the impinging particles is investigated. The magnesium layer thickness is kept well below the mean free path in Magnesium (Mg) to reduce the influence of the carrier recombination in the metal film. The I-V characteristics of such Schottky-Diodes show a homogeneous Schottky barrier of 0.68 eV. The reverse current is below 100 pA. Based on the X-Ray photoelectron spectroscopy (XPS) spectra recorded, it can be demonstrated that the magnesium films are not pre-oxidized. A particular focus lays on the determination of the influence of hyperthermic oxygen on the kinetics of the oxidation process. The kinetic energy of the oxygen molecules could be varied between 25 and 300 meV by adding helium. The chemical current measurements with constant kinetic energy confirms the nucleation and growth model. Measurements with different oxygen velocities demonstrate that the reaction efficiency increases with kinetic energy of the molecules.