Dresden 2017 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 39: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth II
O 39.7: Vortrag
Dienstag, 21. März 2017, 15:30–15:45, WIL C107
Plasma-assisted growth of VO2 on TiO2(110) and study of its chemical and structural properties — •Simon Fischer, Jon-Olaf Krisponeit, Jan Ingo Flege, and Jens Falta — Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany
With VO2 exhibiting a temperature-induced metal-insulator transition, thin film growth of this material is of interest for various applications such as switching devices and sensors. The transition is accompanied by a structural change from a monoclinic insulating phase, in which vanadium atoms are dimerized, to a rutile metallic phase. Since a multitude of different vanadium oxides can form, VO2 growth by molecular beam epitaxy poses challenges in selecting a viable oxidation source and adjusting growth temperature as well as metal-oxygen ratio.
In this study, we have deposited vanadium on TiO2(110) samples continuously and subjected the sample cyclically to different doses of atomic oxygen from a plasma source. Between growth cycles film thickness as well as vanadium oxidation state was determined from x-ray photoelectron spectroscopy analysis. While atomic oxygen is critical in ensuring VO2 stoichiometry, apparently high doses of atomic oxygen lead to the formation of a V2O5 capping. This observation is supported by ex-situ transport measurements. Furthermore, we discuss different surface reconstructions revealed by low-energy electron diffraction in terms of surface oxygen concentration.