Oxygen amount effect on optical properties of aluminium oxide nanostructured films prepared by reactive magnetron sputtering

A simple method was used to deposit the aluminium oxide thin films. Thin films were prepared by reactive magnetron-sputtering on soda glass substrate and the effect of introduced oxygen flow on optical properties of thin films was studied. Structural and optical properties of thin films were characterized and their optical constants were measured. Results revealed formation of cubic aluminium oxide phase. The average grain size of 25 nm was observed by scanning electron microscopy images. Optical spectra of thin films are measured and the effect of oxygen gas amount in sputtering process on the samples is investigated where the highest transmission value belongs to highest amount of introduced oxygen. A new precise approach has been used to measure optical properties of the films. The refractive index and extinction coefficient of the thin films were also measured where the thin films exhibited refractive indexes more than 1.65 at visible wavelengths.