Effect of Ti:ZnO Layer on the Phase Transition and the Optical Properties of VO2 Film

VO2 single-layer and VO2/Ti:ZnO bilayer thin film samples were stabilized on quartz substrates by using sputtering technique, and their structural, morphological and optical properties were investigated. The X-ray diffraction (XRD) results confirmed that VO2 stabilized in the mono-clinic structure in both the samples. Temperature-dependent XRD results demonstrated that the monoclinic-to-rutile structural phase transition temperature had shifted in bilayer sample as compared to VO2 single-layer sample. A uniform surface morphology was realized in both samples, as shown by atomic force microscopy. UV-vis spectroscopy results revealed a significant improvement in the optical transmission in the VO2/Ti:ZnO bilayer thin-film sample. Improved visible transmittance of bilayer sample identifies it as a good candidate for smart window applications.