International Journal of Science, Engineering and TechnologyAuthors: Anil Manjula Ramdas Bari
Abstract: Nanostructured zinc oxide (ZnO) thin films were deposited on ultrasonically cleaned glass substrates using a sol–gel dip-coating technique. Zinc acetate dihydrate, ethanol, and ammonium hydroxide were used as the starting materials. Films with different numbers of coating cycles were prepared and subsequently annealed at 500 °C for 1 h. The structural, morphological, elemental, electrical, and optical properties of the films were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), electrical conductivity measurements, and UV–visible spectroscopy. The crystallite/grain size increased with increasing number of coating cycles. The films exhibited nonstoichiometric ZnO composition and transparent surface morphology. The optical band-gap energy obtained from the absorption spectra was found to depend on the number of coating cycles. The electrical activation energy also increased with increasing grain size. These results demonstrate that the structural and optical properties of sol–gel-derived ZnO thin films can be modified by controlling the number of coating cycles.
