Regensburg 2022 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: Poster

DS 20.44: Poster

Wednesday, September 7, 2022, 16:00–18:00, P3

Different approaches to deposit tungsten-doped vanadium dioxide by ion-beam sputter-deposition — •Jill Kessler, Sebastian Leonard Benz, Isabel Müller, Martin Becker, and Sangam Chatterjee — Institute for Exp. Physics I and Center for Materials Research (LaMa), Justus Liebig University Giessen, Germany

The complexity of the phase diagram of vanadium oxides makes the reproducible growth of thin films of defined phases by nonequilibrium techniques challenging. Here, we discuss thermochromic VO₂, which exhibits a significant change in optical transparency and reflectivity and, thus, is an ideal candidate for the use in smart windows. However, the bulk phase transition temperature of 68 ^∘C is too high for useful applications. Doping VO₂ with tungsten drives the thermochromic key measures close to the desired range.

We present different approaches for tungsten doping of VO₂ based on ion-beam sputter-deposition. We employ tungsten screws that are inserted into the vanadium target. Furthermore, a pre-doped vanadium target is used. In another approach we employ two targets of vanadium and tungsten, respectively, to be sputtered simultaneously. Here, a compositional gradient allows for identification of the optimum doping concentration. The different approaches are compared regarding thin film properties and overall reproducibility of the growth process.

Raman spectroscopy and X-ray photoelectron spectroscopy provide structural and compositional analysis. UV/Vis/NIR spectroscopy yields the thermochromic performance.