APCVD of thermochromic vanadium dioxide thin films—solid solutions V2−xMxO2 (M = Mo, Nb) or composites VO2 : SnO2

Abstract

Atmospheric pressure chemical vapour deposition of V_2−xM_xO₂ (M = Mo, Nb; X = 0.01–0.003) thin films was achieved on glass substrates from the reaction of VOCl₃, H₂O and MCl₅. Comparable reactions with SnCl₄ formed SnO₂ : VO₂ composites. The ease with which solid solutions or composite films formed was related to the relative reaction rates. The films were characterised by X-ray diffraction, Raman, X-ray photoelectron spectroscopy and scanning electron microscopy. Doping of the VO₂ phase was shown to affect both the growth morphology and the thermochromic properties of the films. The Mo-doped VO₂ films showed a thermochromic switch of 47 °C with a narrow hysteresis (4–6 °C).