Characterization of ZnO thin films elaborated by cathodic sputtering with different oxygen percentages: Investigation of surface energy.

Abstract

In this work, transparent thin films of Zinc Oxide (ZnO) were elaborated by RF sputtering with different oxygen percentages (10%, 20%, 30%, 50%). A structural (X-ray Diffraction) and morphological (Atomic Force Microscopy) study was carried out to investigate the influence of the elaboration conditions. A high roughness was obtained for the ZnO film deposited with 50% of O2 under 100w RF power, and the roughness increased with increasing O2 rate. The physicochemical properties were characterized by the calculation of surface energy, the results showed that the surface of the ZnO thin films are governed by short-range forces, i.e. the dispersive component (LW) is larger than the polar component (AB). The calculation of the interaction energy (ΔG iwi ) has shown that the surfaces of ZnO films are hydrophobic (ΔG iwi <0) and the degree of hydrophobicity increases with increasing oxygen percentage.