Influence of substrate temperature on the optical properties of ion-assisted reactively evaporated vanadium oxide thin films

The properties of vanadium dioxide (VO2) films bombarded with oxygen ions during deposition are examined as a function of substrate temperature. Electrical and optical properties of the as-deposited films are discussed. After annealing to the VO2 form, these films exhibit phase transition temperatures reduced from a nominal 67 0C, the lowest thus far in this series being 38 0C. Rutherford backscattering analysis indicates low-level tungsten contamination of the films, presumably from the ion gun filaments. The contaminant has a role in properties modification but does not provide a complete explanation for our observations