Rapid-melt-mediated recrystallization of ZnO thin films grown at low temperature by using KrF excimer laser irradiation

ZnO thin films with thickness of 150 nm were grown on ITO/glass (ITO-coated glass) substrates by using the radio-frequency (RF) sputtering technique at 400 °C in an Ar atmosphere. An excimer laser irradiation (ELI) treatment was performed on the surface of ZnO thin films at different excimer laser energy densities of 150, 200, and 250 mJ/cm² in a N₂ atmosphere. The ELI treatment promoted the lateral recystallization of the surface area of the ZnO, resulting in a significant improvement of the crystallinity of the ZnO thin films without substrate damage. As-grown ZnO and ELI-treated ZnO thin films were characterized by using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The analyses showed that the ZnO thin film treated with ELI at an excimer laser energy density of 150 mJ/cm² exhibited the best structural properties.