In-situ XRD study on phase transition kinetics of vanadium dioxide thin film

Abstract

Vanadium dioxide (VO₂) has great potentials to be used in energy-related fields due to its unique reversible thermochromic metal-insulating properties. In this paper, we used in-situ XRD technique to study the phase transition kinetics of VO₂ thin films, which can change phase from monoclinic VO₂ (M) to tetragonal rutile VO₂ (R). The VO₂ thin films were prepared by a simple solution-based sol-gel method followed by spin coating to achieve the nanoscale thickness on a quartz substrate. During heating, the critical phase transition of VO₂ (M) occurred at 70 °C, which dropped to 45 °C during cooling. A martensite-like crystal phase transformation kinetic model was established based on the Koistinen and Marburger (KM) technique. The relative content of the two phases was quantitatively analyzed using the Rietveld method, and the transformation rate coefficient α was obtained as 0.20345 and 0.12585, for the heating process from VO₂ (M) to VO₂ (R) and the cooling process from VO₂ (R) to VO₂ (M), respectively. This research offers an effective tool for understanding the structural characteristics of thin film VO₂, paving the way for its future design and applications towards energy-related fields such as in smart windows.