A new approach in pulsed laser deposition of VO2 (M1)-VO2 (B) nanocomposite thin films

Abstract

Vanadium dioxide (VO₂) is a material that has garnered significant attention owing to its unique properties of its insulator-to-metal phase transition (IMT). VO₂ can exist in different polymorphic phases, each with distinct properties. The coexistence of VO₂ (M1) and VO₂ (B) phases has attracted increasing interest due to their impacts on the IMT. Further, films containing mixed M1 and B phases are of particular interest for technological applications. In the present study, we employed pulsed laser deposition to produce mixed VO₂ (M1) and VO₂ (B) nanocomposite films on glass substrates. This was accomplished by exploring the target-substrate distance. Our findings indicate that increasing the deposition distance results in a transition from a solely VO₂ (M1) phase to a composite phase that includes both VO₂ (M1) and VO₂ (B). This transition is associated with improvements conductivity, infrared reflectivity, and the symmetry of the hysteresis loop, while maintaining the essential features of the phase transition, such as hysteresis width, contrast, and sharpness, which are related to the improvement of structural properties. This observation stands in contrast to earlier studies that suggested a reduction in the IMT strength. Accordingly, our study provides important perspectives that can greatly improve the practical application of VO₂.