The growth behavior of VO2 crystal film deposited on Al2O3 (0001) monocrystalline substrate by pulsed laser deposition was investigated by high-resolution synchrotron radiation X-ray diffraction (XRD). φ-scan XRD confirmed the in-plane epitaxial matching relation. Furthermore, fine structures observed in the φ-scan indicated that each main peak contained two additional satellites in both the inclined (220) plane and some other vertical planes. A growth model for this observation was proposed based on the intrinsic multi-domain growth of the VO2 crystal at the interface. This observation will give some insights in VO2 epitaxial growth on the hexagonal substrate system.
Tungsten-doped VO2 thin films have been synthesized by a modified sol–gel process and followed by a post annealing. Vanadium pentoxide and tungstic acid as raw materials with the addition of hydrogen peroxide, concentrated hydrochloric acid (catalyst) and oxalic acid used as reducing agent were reacted in isobutanol. Finally, the uniform sol of vanadyl oxalate in isobutanol solvent was obtained as precursor. Detailed study suggested that W doped in VO2 introduces additional electron carriers and induces the formation of V3+. Post annealing under vacuum promotes the releasing of chemical stress and generates oxygen vacancies in the samples. Temperature dependent transmittance study revealed that the releasing of chemical stress and deliberately introducing oxygen vacancies in W-doped VO2 films have positive effects on enhancing its switching ability in the infrared transmittance as the metal-insulator transition (MIT) occurs. The largest switching of transmittance was obtained about 48% in the infrared range at 43 °C in 1.5%W doped VO2 films, which is significantly larger than the reported ones. The findings in this work open a new way to synthesize the novel and thermochromic W doped VO2 films with facility and low cost. Therefore, it has extensive application to construct smart windows and electronic devices.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.