Raman spectroscopic characterization of the microstructure of V2O5 films

The vanadium pentoxide (V₂O₅) films were deposited on silicon wafer by DC magnetron sputtering. By Raman scattering measurements, the microstructure properties of the V₂O₅ films prepared with different O₂–Ar gas flow ratios and annealed at different temperatures were studied, respectively. The results revealed that the increase of O₂–Ar gas flow ratio during sputtering was of advantage to prepare the V₂O₅ film with desired layer structure. A high post-annealing temperature (below 500 °C) induced the crystallization and the formation of the integrated structure of V₂O₅ film. However, it was found that both intensities of Raman scattering peaks at 146 cm^?1 and 994 cm^?1, respectively, decreased for samples annealed at a temperature of 550 °C. The peak at 146 cm^?1 was attributed to skeleton bent vibration and that at 994 cm^?1 was due to the stretching vibration of vanadyl V=O_A bond. It showed that the high-temperature annealing was believed to have distorted the microstructure of V₂O₅ films. The oxygen vacancies were, therefore, induced, which benefited the formation of V-O_A-V bonds between layers. The result of X-ray diffraction measurements was in good agreement with that of Raman scattering spectra.