High quality VO₂ thin films synthesized from V₂O₅ powder for sensitive near-infrared detection

Vapor transport method has been successfully used to synthesize high quality VO₂ thin films on SiO₂/Si substrate using V₂O₅ as a precursor in an inert-gas environment. The morphological and structural evolutions of the intermediate phases during the nucleation and growth processes were investigated by SEM and Raman spectroscopy, respectively. The results showed that the conversion of V₂O₅ powder to VO₂ thin films was dominated by a melting-evaporation-nucleation-growth mechanism. Further characterization results demonstrated that the high quality crystals of monoclinic VO₂ thin films exhibit a sharp resistance change up to 4 orders of magnitude. In addition, the VO₂ thin films exhibited good near-infrared response, high stability, and reproducibility under ambient conditions, which should be promising for sensitive near-infrared detection. Our work not only provided a simple and direct approach to synthesize high quality VO₂ thin films with distinct phase transition properties but also demonstrated the possible infrared sensing application in the future.