Surface Wettability of ZnO Thin Films

In this study, zinc oxide (ZnO) structured films were grown on glass substrates using a simple chemical bath deposition (CBD) method with different salt precursors. The variation of salt precursors towards the surface morphology of thin films and its wettability properties were investigated. Four types of zinc (Zn) salt used as precursors are zinc chloride (ZnCl2), zinc acetate (ZnAc2), zinc nitrate (Zn(NO3)2) and zinc sulfate (ZnSO4). The crystallinity of ZnO thin films was evaluated using X-ray diffraction (XRD), and the surface morphology was observed using field emission scanning microscopy (FESEM). Finally, the wettability was determined by contact angle (CA) measurement. It was found that ZnCl2 has the lowest CA (127.1°), while ZnSO4 exhibits the highest CA (142.3°). The Zn salts used significantly influenced the thin film surface morphology, resulting in varied wetting behaviour depending on the surface roughness.