Effect of nonstoichiometry on Raman scattering of VO₂ films

We report on Raman scattering of VO_2 films prepared by radio frequency magnetron sputtering under different conditions. Our investigations revealed that the dominated Raman peaks shift towards high frequency for both V-rich and O-rich VO_2 films, compared with the stoichiometry VO_2 films. The experimental evidence is presented and the cause for nonstoichiometry dependence of Raman spectra of VO_2 films is discussed.