Regensburg 2022 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 28: Transport in Materials: Diffusion / Electrical Transport & Magnetism

MM 28.1: Talk

Thursday, September 8, 2022, 10:15–10:30, H44

Electrical resistivity of magnetron-sputtered Fe_1−xO thin films — •Simon Evertz¹, Nina Nicolin¹, Daniel Primetzhofer², James P. Best¹, and Gerhard Dehm¹ — ¹Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany — ²Department of Physics and Astronomy, Uppsala University, S-75120 Uppsala, Sweden

Fe_1−xO (wüstite) is a critical phase for a number of applications in the future hydrogen economy, such as photochemical materials for H₂ production by water-splitting. Hence, charge transport is crucial for the applicability of Fe_1−xO in electrode materials. To probe the charge transport of close-to-stoichiometric Fe_1−xO, thin films were synthesized by reactive magnetron sputtering with systematically varied O₂ gas flow. The phase formation and chemical composition was correlated to the electrical resistivity and mechanical properties, as measured in a van-der-Pauw-setup and nanoindentation, respectively. The charge transport mechanism is shown to change from thermally activated hopping of charge carriers - typical for a semiconductor - to metallic-like behavior as a function of the phase purity of the films. By correlative analysis of phase purity, microstructure and mechanical properties, it is shown that already small amounts of Fe as impurity phase are decisive for changing the charge transport mechanism. These significant changes in charge transport are further compared to the hardness and Young’s modulus of these films.