Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 89: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I

O 89.2: Vortrag

Donnerstag, 15. März 2018, 10:45–11:00, MA 041

VO₂ growth on TiO₂(110) using atomic oxygen — •Simon Fischer, Jens Falta, Jan Ingo Flege, and Jon-Olaf Krisponeit — Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany

VO₂ thin film growth is of interest for switching devices and sensorics because it exhibits a temperature-induced metal-insulator transition. This is accompanied by a structural change between a monoclinic insulating phase and a rutile metallic phase, allowing for tuning the transition temperature by choice of the substrate: TiO₂(110) as a substrate applies in-plane tensile strain to the rutile c-axis and thus increases the transition temperature, favoring the monoclinic phase.

VO₂ growth is challenging in terms of achieving the correct stoichiometry, which is why we used an activated oxygen source. We examined the deposition of 5 to 10 nm of VO₂ on TiO₂(110) in-situ using LEEM and LEED. Additionally, from XPS measurements we determined the stoichiometry by analyzing the chemical shift of the V2p_3/2 peak and we estimated the film thickness from the attenuation of the substrate peak. High doses of atomic oxygen enable the formation of V₂O₅ domains of random azimuthal orientation, while lower doses lead to oxygen vacancies that impair transition characteristics as observed in ex-situ measurements.

Financial support from the DFG is acknowledged.