Effect of the annealing time on the physico-chemical properties of WO3 thin films prepared by spray pyrolysis

• Published in: Materials chemistry and physics Vol. 70; no. 1; pp. 84 - 89
• Main Authors: Regragui, M., Addou, M., El Idrissi, B., Bernède, J.C., Outzourhit, A., Ec-chamikh, E.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 02.04.2001; Elsevier
• Subjects: Annealing time; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physico-chemical properties; Physics; Spray coating techniques; Thin film; Tungsten trioxide; Physico-chemical properties; Tungsten trioxide; Annealing time; Thin film; Pyrolysis; Infrared spectroscopy; Spray coatings; Hot spraying; Processing time; Tungsten oxides; XRD; Experimental study; Photoelectron spectroscopy; Heat treatments; Thin films; SEM; Physicochemical properties
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/S0254-0584(00)00464-8

Tungsten trioxide (WO3) thin films were prepared by spray pyrolysis. The obtained films were amorphous and dark-brown. The films were subsequently annealed at 500°C in an air atmosphere for different annealing times. The IR measurements revealed the presence of water in our films and enabled us to follow its evolution as a function of the annealing conditions. The composition of the films was investigated by X-ray photoelectron spectroscopy. W 4f and O 1s core level peaks were decomposed and all the hidden peaks were identified. The XRD study showed that the crystallinity increased with the annealing time. The optical study indicated that the annealed films were transparent. The optical gap and the refractive index were found to be in agreement with data in the literature. Nevertheless, spectral measurements of the diffuse transmittance showed that this component was significant and varied with the annealing time.