Effect of annealing temperature on the morphological, structural, and optical properties of zinc oxide nanostructures prepared by the sol–gel spin coating technique

Abstract

ABSTRACT This study investigates the impact of different annealing temperatures on the properties of zinc oxide (ZnO) films, particularly at lower temperatures (150-550°C). The films were synthesized using the sol-gel technique, with zinc acetate dihydrate (ZAD) as the precursor and ethanolamine (MEA) as the stabilizing agent. Surface morphology, structural, and optical properties of the films were examined using various techniques. X-ray diffraction confirmed the (002) wurtzite crystal structure, while crystallite size, strain, stress, energy density model, and dislocation density are estimated using three models of Williamson-Hall (W-H) approach.Raman data indicated the hexagonal wurtzite structure of the film. Optical analysis showed good transmittance, with a bandgap estimated between 3.32 and 3.56 eV for all samples. SEM image analysis revealed a nanowall structure in the ZnO thin film annealed at 150°C. However, increasing the annealing temperature led to a more pronounced wrinkled morphology.