Tuning of surface properties of AZO thin films through substrate configuration variation

Abstract

This study investigates the influence of substrate configuration variations on the surface properties and contact angle of nanostructured aluminum-doped zinc oxide (AZO) thin films deposited via RF magnetron sputtering on glass substrates at room temperature. Three distinct substrate configurations—Standard Planar Position (SPP), Glancing Angle Deposition (GLAD), and Twisted Standard Planar Position (TSPP)—were employed to explore their impact on the films structural morphology and crystallinity, characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). Wettability, characterized by contact angle and surface energy, was assessed using static measurements with a range of probe liquids, including water, diiodomethane, and ethylene glycol. Our findings demonstrate the ability to tailor AZO films to achieve specific crystalline orientations without altering the growth temperature. Substrate rotation and configuration modifications significantly impacted AZO film surface energies, revealing enhanced hydrophilicity evidenced by reduced contact angles compared to control samples. Using the Owens–Wendt-Kaelble method, we quantified both polar and dispersive surface energy components, observing significant increases in both for AZO thin films. These results highlight heightened surface reactivity, suggesting potential applications in diverse wetting-dependent contexts, such as reinforcement of polymeric materials and self-cleaning surfaces and anti-reflective coatings for photovoltaic devices.