Raman and XPS characterization of vanadium oxide thin films deposited by reactive RF sputtering

In this paper we report on Raman and XPS characterization of vanadium oxide thin films deposited by RF-sputtering. The samples were deposited by using a vanadium target in different oxygen fluxes, so that the stoichiometry (O /V ratio) of the oxide was varied. Several physical parameters of the films indicate a strong structural difference between the sample deposited at lo wer oxygen flux (1 scc m) and those obtained with higher flux (from 1.25 to 9 scc m). The increase of OV ratio corresponds to a lower crystallinity of the thin films as indicated by the initial lowering and the final disappea rance of the characteristic Raman mode of V2O5 (crystal) at about 140 cm(-1 ). For the highest flux samples new broad bands develop, typical of amorpho us materials, both in polarized as well as in depolarized Raman spectra. (C ) 1999 Elsevier Science B.V. All rights reserved.