Effect of varying the vanadium thickness layer of V₂O₅/V/V₂O₅ film on its microstructural and thermochromic properties Available to Purchase

In this study, V₂O₅/V/V₂O₅ sandwich-structured films were deposited on glass substrates by electron beam evaporation. The thickness of the first (bottom) V₂O₅ layer was 40 nm and the last (top) layer was 20 nm, while that of the sandwiched vanadium layer varied up to 12 nm for different samples. The effects of varying the thickness of the sandwiched vanadium layer on microstructural and thermochromic properties of the as-deposited and thermal annealed films were investigated. Ultrahigh-resolution scanning electron microscopy revealed the presence of nanostructures with various irregular shapes on the surfaces of all films. Also, the atomic force microscopy revealed an average roughness of ∼10–38 nm for increasing thickness of the sandwiched vanadium layer. X-ray powder diffraction measurements showed the presence of the monoclinic VO₂ (M) crystal structure of the films with (011) preferred orientation at 27.94° for both 7 and 12 nm thicknesses of the sandwiched vanadium layers. The varying thickness of the sandwiched vanadium layers enhanced phase transition temperature values to ∼33.92 and ∼29.11 °C for both 7 and 12 nm thicknesses of the sandwiched layers, respectively. These enhanced transition temperature values, as a result of thickness variation of the sandwiched vanadium layers, pointed toward utilization of this method in the successful synthesis of VO₂ films for thermochromic windows application and optoelectronics.