Studies on the optical properties of ZnO nanostructured thin films synthesized by RF magnetron sputteringAuthor(s): B.Khalfallah, F.Chaabouni, M.Abaab
Zinc oxide (ZnO) thin films were deposited by RF magnetron sputtering onto glass substrates at room temperature. The thickness effect on the structural,morphological and optical properties of the ZnO filmswasstudied. Films thickness was calculated by interference fringes method and varied from 360 nm to 680 nm. The grain size was in the range of 26 - 29 nmcorresponding to nanostructured films. Stress values at different thickness were investigated. The root mean square roughness of the films increased from 3.3 to 12.2 nm in the thickness range of investigation. The average optical transmittance of the films was about 85 % in the visible region. The optical band gap of the ZnO films decrease from 3.37to 3.09 eV with increasingfilm thickness. The refractive index dispersion and dielectric constants were investigated by Cauchy, Wemple-Didomenico and Spitzer- Fanmodels. The results demonstrated that the optical properties were highly related to structural ones. The obtained films can be used as transparent electrodes in solar cells.