The optical properties of amorphous V2O5 and SiO thin films and of the mixed dielectric system SiO/V2O5

Abstract

The optical absorption of amorphous thin films of V2O5, SiO and of SiO/V2O5 is studied in the photon energy range 0.42 to 6.53 eV. The optical absorption edge of evaporated V2O5 films can be described by direct forbidden transitions while that of SiO films follows the non-direct transitions in k-space. The data of the SiO/V2O5 oxide mixtures are fitted to new values of the exponent in the well-known absorption equation and the corresponding optical band gaps are determined. Experimental data on the wavelength dependence of the refractive index of SiO films are presented. The dispersion of the refractive index follows a single oscillator model. The infrared spectra show that some bonding occurs between the two oxides so that the mixed dielectric system SiO/V2O5 cannot be considered as a simple physical mixture.