<p>This work demonstrates the deposition of n-type zinc oxide (ZnO) and Yttrium (Y) doped ZnO (Y-ZnO) thin films on quartz glass substrates with the variation of the concentration of Y at different percentages (1, 3, and 5 at. %) as the dopant. ZnO and Y-ZnO films were successfully deposited using the sol–gel spin coating method and subsequently annealed at 500 °C. Deposited thin films exhibited well-defined polycrystalline structures with a hexagonal wurtzite crystal configuration. Y doping effect in ZnO thin film was investigated from of structural, morphological, and optical analysis. Synthesized thin films were characterized by means of X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Electron Dispersive Spectroscopy (EDS), and Ultraviolet-visible (UV-vis) spectroscopy. XRD patterns indicated the decreased crystallinity in 1% Y doping with some impurity content and less intense peaks compared to undoped ZnO. However, this drawback was improved significantly in case of 3% and 5% Y doping due to the successful substitution of Zn²⁺ site by Y³⁺ ion in ZnO lattice. As dopant concentration increased, the increment trend of crystallite size (from 2.16 to 8.87 nm) was also observed. SEM examination demonstrated Y’s domination over ZnO thin film morphology. The particles mostly showed agglomeration and irregular forms, with an average size ranging from 44.96 nm to 27.24 nm. The EDS spectrum confirmed the presence of Zn, O, and Y elements. Additionally, all the synthesized thin films demonstrated high transparency in the visible range, with values ranging from 81.54% to 89.83%. Because of the dopant element’s dispersion, the high transparency that was seen in the undoped ZnO thin film dropped to 87.7% in the 5% Y doping. The bandgap was reduced from 3.22 to 3.06 eV with the increment of the dopant concentration due to the quantum confinement effect.</p><p></p>