Sabrina Roguai 1Abdelkader Djelloul 22024-02-142024-02-142023-07-1402319-7064http://dspace.univ-khenchela.dz:4000/handle/123456789/1050/Zn1-xCoxO thin films (x=0-22 at.%) were prepared using the ultrasonic pyrolysis sputtering technique. The films have a hexagonal wurtzite structure, confirmed by X-ray difraction, with an estimated average crystallite size in the range of 18-30 nm. Concerning the optical properties, by applying the Levenberg-Marquardt least squares method, the experimental transmittance data were perfectly fitted with the transmittance data calculated via a combination of the Wemple-DiDomenico model, the absorption coefficient of an electronic transition and the Tauc-Urbach model. Decreases in bandgap energy due to the presence of high concentrations of localized states in thin films were calculated from the Smakula formulaenArticle