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O: Fachverband Oberflächenphysik
O 89: Poster Session - Oxide and Insulator Surfaces: Structure, Epitaxy and Growth
O 89.2: Poster
Mittwoch, 18. März 2020, 18:15–20:00, P2/1OG
Morphological study of vanadium dioxide (VO2) thin films grown on the different substrates using STM — •Aman Baunthiyal, Simon Fischer, Jon-Olaf Krisponeit, and Jens Falta — Institute of Solid State Physics, University of Bremen, Germany
Vanadium dioxide (VO2) is an interesting material for sensor and memory devices due to its metal-insulator transition (MIT) near room temperature (RT) that is accompanied by a structural change between a monoclinic insulator phase and a rutile metallic phase. This temperature can be varied by the choice of the substrate: TiO2(110) and RuO2(110) applies in-plane tensile strain to the rutile c-axis which leads to an increase of the transition temperature of VO2, favoring the monoclinic phase.
RuO2(110) islands were formed on the surface of a Ru crystal by oxidizing it while observing with in-situ LEEM and LEED. Then, VO2 was deposited using molecular beam epitaxy (MBE). VO2 growth on TiO2(110) substrate was grown through the same process. To study the surface morphology of VO2 grown on RuO2(110) and TiO2(110), we used STM (scanning tunneling microscope) at RT. In the case of VO2/RuO2, the surface of VO2 was found flat with two rotational domains separated by 60 degrees. The thickness of VO2 on RuO2 was measured to be about 3 to 4 nm using XRR (X-ray Reflectometry). In the case of VO2/TiO2 , the surface was also found to be flat but showing small grains of VO2 on the TiO2 surface. Next, we intend to study the effect of different substrates on the MIT transition of VO2 by variable temperature STM (VT-STM) using single-point spectroscopy.