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=OA 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-OA-V bonds between layers. The result of X-ray diffraction measurements was in good agreement with that of Raman scattering spectra.