An Effect of Precursor Concentration on ZnO Thin Films Prepared by Dip Coating Method

Zinc Oxide (ZnO) thin films have been successfully coated onto glass substrates at various solutions
concentration (0.1 M, 0.2 M and 0.3 M) by Low cost SILAR coating technique. The film thickness was
estimated using weight gain method and it revealed that the film thickness increased with solution
concentration values. The prepared film structural, morphological and optical properties were studied
using X-ray diffraction (XRD), scanning electron microscope (SEM) and UV-Vis-NIR
spectrophotometer respectively. The structure of the films were found to be hexagonal structure with
polycrystalline in nature with preferential orientation along (002) plane. X-ray line profile analysis was
used to evaluate the micro structural parameters such as crystallite size, micro strain, dislocation
density and stacking fault probability. The value of the crystalline size is increased by increasing the
concentration of the solution. The average crystalline size was estimated at in the range of 26 nm to
29 nm. The morphological results showed that the concentration of a solution had a significant effect
on the morphology of the ZnO thin films. The optical studies revealed that the band gap can be
tailored between 3.65 eV to 3.85 eV by altering solution concentration. EDAX studies have shown the
presence of zinc and oxygen content. Photoluminescence intensity varies with molar concentration
due to the increase of oxygen vacancies. FTIR results conforms the presence of functional group
present in the samples.