Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 44: Poster III: Focus session: Resistive switching by redox and phase change phenomena

DS 44.6: Poster

Thursday, April 3, 2014, 16:00–19:00, P1

Growth and characterization of free-standing VO₂ nanowires — Matthias Ogrisek, •Tim Barth, Jura Rensberg, and Carsten Ronning — Institut für Festkörperphysik Friedrich Schiller Universität Jena

Recently, Vanadium dioxide has attracted much attention because of its "metal to insulator transition (MIT)" at ≈68^∘C. This transition causes a significant change of the electrical and optical properties, allowing applications like sensing or switching. The growth of high-quality VO₂ films is challenging due to stress caused by different thermal expansion coefficients and a lattice mismatch between the film and the substrate. For this reason the growth of VO₂ nanowires (NW’s) is of particular interest, because stress can quickly relax laterally in NW’s. The aim of our study was to grow free-standing VO₂ NW’s. The wires have been grown in a 3-zone tube furnace utilizing Vapor-Solid (VS) growth. VO₂ powder was placed in an alumina boat and heated up to 1325 K to evaporate. The vapor was transported to the substrate by an argon gas flow and grew the wires by self alignment. In-plane grown wires had a length of 200 µm and a diameter of 1-2 µm. Out of plane growth of the nanowires has been achieved by using r-plane sapphire substrates but caused a decrease of the wirelength to 10 µm. EDX-spectrometry revealed only vanadium and oxygen signals and the Raman spectrum measured at RT confirmed the VO₂ nature of the nanowires.