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MM: Fachverband Metall- und Materialphysik

MM 34: Poster session II

MM 34.20: Poster

Dienstag, 21. März 2017, 18:30–20:30, P4

Mechanically tuned stress state of palladium thin films on rutile titanium dioxide — •Maximilian Litschauer¹, Marian David Bongers¹, Daniel Harding², Alec Wodtke², and Astrid Pundt¹ — ¹Institut für Materialphysik, Univ. Göttingen — ²Institut für Physikalische Chemie, Univ. Göttingen

The mechanical stress state of epitaxially grown palladium (Pd) thin films on Al₂O₃ single crystals can be varied by the film thickness [1]. This stress state may also affect the surface conditions, for example by modifying the distance between the Pd surface atoms. This should result in a modified surface reactivity as suggested for example by the d-band model of Mavrikakis et al. [2]. In this study the stress states of differently prepared Pd films on titanium dioxide (TiO₂) is presented and the binding energies (BE) of carbon monoxide (CO) on these surfaces is determined. Therefore, the deposition temperature and film thickness of Pd thin films are varied. The films are deposited by magnetron sputtering on pretreated TiO₂(110) substrates. The stress state is characterized by X-ray diffraction via the Pd(111) peak shift. The related BE are addressed by using a novel ion imaging technique to directly measure the microsecond lifetime of CO on the surface [3]. The results are discussed with respect to the mechanical stress states.

This study is supported by the Deutsche Forschungsgemeinschaft via SFB1073, project C06 and C04 as well via the Heisenberg grant PU131/9-2. [1] S. Wagner et al., Acta Materialia 114 (2016) 116; [2] M. Mavrikakiset al., Phys. Rev. Lett. 81 (1998) 2819; [3] D. J. Harding et al., J. Phys. Chem. A 119 (2015) 12255