Tailoring Epitaxial VO₂ Thin Films with Tunable Properties via Spray Pyrolysis

Significant advancements have been made in the past few decades in the precise control of VO₂ synthesis, enabling the creation of structures with diverse morphologies and distinct phase transition properties. Existing synthesis methods used in research settings are often inadequate for large-scale production, particularly concerning high-quality VO₂ thin films. Addressing these synthesis obstacles is crucial to unlocking the full potential of VO₂ and harnessing its multifunctional properties for a broad range of practical applications. In this study, we highlight the low-cost, nonvacuum, and high-yield spray pyrolysis technique as a promising method for fabricating high-quality VO₂ thin films. We successfully synthesized high-quality epitaxial VO₂ thin films on a c-plane Al₂O₃ substrate using spray pyrolysis. Two approaches were employed: direct growth in a nitrogen-oxygen environment and growth of V₂O₃ in a nitrogen atmosphere, followed by postannealing in a nitrogen-oxygen mix. Both methods yielded relatively high-quality VO₂ films with metal-insulator transition properties comparable to those achieved by more sophisticated growth techniques. However, we observed some differences in the electrical and structural properties between the two fabrication approaches. These findings highlight the potential of spray pyrolysis as a cost-effective and scalable technique for the production of high-quality functional VO₂ thin films, providing an alternative to conventional growth methods. Optimization of growth parameters and processes is essential for achieving the desired electrical and structural properties in spray pyrolysis-synthesized VO₂ films.