Effects of process parameters on the optical constants of highly textured VO thin films.

The optical properties of the highly-textured VO thin-films grown on Si(100) by sputter-deposition at various oxygen reactive-pressures were investigated in detail. The profiles of the optical constants, namely the refractive index and extinction coefficient, of VO films were evaluated in the photon-energy range of 1-5 eV. At photon-energy above 2.5 eV, the dispersion behavior in optical constants is explained based on Lorentz-Drude model. The refractive index dispersion fits to a Cauchy's relation at photon-energy below 2.5 eV, where the VO-film is mostly transparent. The optical transitions across the bandgap occur at energy ∼2.5-3.2 eV depending on the VO growth conditions and film-microstructure. The highly-textured and c-axis oriented VO-films, fabricated under optimum conditions of temperature and oxygen partial pressure, exhibit excellent optical characteristics similar to VO single crystals. [ABSTRACT FROM AUTHOR]