Raman Study of Novel Nanostructured WO₃ Thin Films Grown by Spray Deposition

Abstract

The present communication reports on the effect of the sprayed solution volume variation (as a thickness variation element) on the detailed Raman spectroscopy for WO3 thin films with different thicknesses grown from precursor solutions with two different concentrations. Walls-like structured monoclinic WO3 thin films were obtained by the spray deposition method for further integration in gas sensors. A detailed analysis of the two series of samples shows that the increase in thickness strongly affects the films’ morphology, while their crystalline structure is only slightly affected. The Raman analysis contributes to refining the structural feature clarifications. It was observed that, for 0.05 M precursor concentration series, thinner films (lower volume) show less intense peaks, indicating more defects and lower crystallinity, while thicker films (higher volume) exhibit sharper and more intense peaks, suggesting improved crystallinity and structural order. For higher precursor concentration 0.1 M series, films at higher precursor concentrations show overall more intense and sharper peaks across all thicknesses, indicating higher crystallinity and fewer defects. Differences in peak intensity and presence reflect variations in film morphology and structural properties due to increased precursor concentration. Further studies are ongoing.

Keywords

• Raman spectroscopy
• tungsten oxide
• spray pyrolysis
• thin films