Structural properties of WO₃ dependent of the annealing temperature deposited by hot-filament metal oxide deposition

In this work presents a study of the effect of the annealing temperature on structural and optical properties of WO3 that has been grown by hot-filament metal oxide deposition (HFMOD). The chemical stoichiometry was determined by X-ray Photoelectron Spectroscopy (XPS). By X-ray diffraction obtained that the as-deposited WO₃ films present mainly monoclinic crystalline phase. WO₃ optical band gap energy can be varied from 2.92 to 3.15 eV obtained by transmittance measurements by annealing WO3 from 100 to 500°C. The Raman spectrum of the as-deposited WO₃ film shows four intense peaks that are typical Raman peaks of crystalline WO₃ (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that are assigned to W-O stretching (υ) and W-O bending (δ) modes, respectively, which enhanced and increased their intensity with the annealing temperature.