Impact of Annealing Temperature on Surface Reactivity of ZnO Nanostructured Thin Films Deposited on Aluminum Substrate

Abstract

In the present work, the fabrication of a hydrophobic surface was carried out by thermal oxidation of thin layers of Zn deposited by electrodeposition on an aluminum substrate under air atmosphere at different temperatures between 400 ˚C and 500 ˚C. Structural analysis by XRD and Raman spectroscopy shows that increasing the annealing temperature leads to the formation of a considerable amount of ZnO on the aluminum substrate. ZnO-bound XRD peaks appear and Zn- and Al-bound peaks decrease. For TS = 400 ˚C and 500 ˚C, the films treated at are polycrystalline with a hexagonal structure of the Wurtzite type due to the existence of the more intense peak relating to the orientation (100) located around the angle 31.75 ˚. EDX analysis gives the chemical composition of these films and confirms the presence of zinc and oxygen in an almost stoichiometric composition. The morphological study of thin layers treated at 500 ˚C shows the coexistence of nanostructures in the form of deformed flowers, which leads to their hydrophobicity. The contact angle values measured are ˃ 90˚ for the films treated at 400 ˚C and 500 ˚C, which confirms the hydrophobic nature with a high value obtained equal to 135˚.