Regensburg 2019 – wissenschaftliches Programm
O 37.5: Vortrag
Dienstag, 2. April 2019, 15:00–15:15, H16
Vanadium dioxide thin films on (100)- and (110)-oriented ruthenium dioxide islands — •Simon Fischer1, Michael Foerster2, Lucia Aballe2, Vedran Vonk3, Jens Falta1, Jon-Olaf Krisponeit1, and Jan Ingo Flege4 — 1Institute of Solid State Physics, University of Bremen, Germany — 2ALBA Synchrotron Light Facility, Barcelona, Spain — 3Deutsches Elektronen Synchrotron DESY, Hamburg, Germany — 4Applied Physics and Semiconductor Spectroscopy, BTU Cottbus, Germany
Bulk vanadium dioxide exhibits a metal-insulator transition at 68 ∘C. Because this change in resistivity is linked to a structural transition, the transition temperature can be tuned by epitaxial strain. Due to the high lattice mismatch of RuO2 with VO2, this substrate promises a highly shifted transition temperature, which enables new types of switching devices, smart coatings, and sensors. It is prepared by oxidizing a Ru(0001) crystal, providing micron-sized, (110)- as well as (100)-oriented RuO2 islands simultaneously.
One of the challenges in preparing VO2 is to reliably meet the desired stoichiometry. We investigated the vanadium oxidation state using local XAS and XPS measurements taken at a synchrotron-based XPEEM instrument, revealing that VO2 stoichiometry is maintained throughout the entire film. This was found not only on RuO2(100) and RuO2(110), but also on the bare ruthenium substrate. The VO2 film thickness was determined to 3.6 nm by ex situ XRR measurements.
Financial support from the DFG is acknowledged.