Impact of Silver on the Structural and Wettability Properties of ZnO Films Grown by Oblique Angle Magnetron Sputtering

Un-doped (uZO) and silver-doped zinc oxide (SZO) films were prepared by oblique incidence sputtering deposition under different process parameters. The crystalline structure, chemical composition, and surface morphology were correlated with the optical properties, as well as with the wettability of the films. In the case of uZO films, the orientation, inclination, and morphology of the columnar structure determined the wettability of the layer, moving from a hydrophilic- to hydrophobic-like character. In the case of SZO films, although almost all of them displayed hydrophobic behavior, the hydrophobic character increased with the Ag content. The most hydrophobic surface was obtained when the Ag content in the layers was greater than 7 at.% and, in these cases, the structural results indicate that the layers were formed by a disordered mixture of Zn and Ag oxides.