The optical and structural properties of amorphous Nb2O5 thin films prepared by RF magnetron sputtering

Nb2O5 thin films were deposited on high temperature glass substrate by reactive RF magnetron sputtering using a  Nb2O5 target in an Ar atmosphere. The relationships between structural and optical properties were studied using XRD, AFM and spectrophotometry. Argon pressure was selected from the range of 3-15 mTorr to investigate its effect on the film properties results showed that as-deposited films were amorphous for all of the deposition pressures and flow ratios used. The refractive indices of the films were in the range 2.00-2.32 at the wavelength of 550 nm depending on the sputtering conditions. The films were also deposited with different thicknesses to determine the effects of the thickness on the optical properties of Nb2O5 films. The films were also deposited at 3 mTorr with the substrate temperature varied from room temperature (RT) to 300 °C. As a result, it is seen that the refractive index increases with the increasing substrate temperature