From multilayers to V1-xWxO2±δ films elaborated by magnetron sputtering for decreasing thermochromic transition temperature

International audienceW-doped monoclinic vanadium dioxide VO2(M) thin films with various W contents were successfully deposited by magnetron sputtering method. As-deposited films consisted of multilayers composed of VO2/W bilayers. Further annealing at 500 °C under Argon for 1 h led to crystallized and homogeneous V1-xWxO2±δ films. 200 nm films were characterized at room temperature by Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Besides, the films were analyzed by temperature-dependent infrared transmittance in the wavelength region 2–25 μm and the effects of W doping on thermochromic properties of VO2 were studied. The results show that the transition temperature gradually decreases with increasing W content. A transition temperature of 21 °C with a high infrared transmittance modulation (≈68%) was finally achieved with a W-doping level of 2.7 at.% which may indicate a strong potential for applications in optical devices as functional materials