Structural and luminescent properties of ZnO flower-like nanostructures synthesized using the chemical bath deposition method

Crystalline zinc oxide (ZnO) flower-like nanostructures were synthesized by the chemical bath deposition (CBD) method. The temperature of the bath was maintained at 80 degrees C. The effect of different mol% of zinc acetate and different synthesis time on the structure, morphology and optical properties of nanostructures were obtained. The X-ray diffraction (XRD) pattern for the ZnO flower-like nanostructures showed crystalline peaks corresponding to a hexagonal wurtzite ZnO structures. There was no effect on the structure as the mol% of zinc acetate and different synthesis time were varied, respectively. The estimated average grain sizes were found to be 45 mu It was found that the estimated grain sizes increases with an increase in zinc mol% and synthesis time, respectively. Scanning electron microscopy (SEM) observations showed the presence of flower-like aggregates. In the case where a higher mol% of zinc acetate and reaction time was used in the preparation process, respectively, the nanoflower-like structures were larger in size. The shape however did not change. Transmission electron microscopy (TEM) micrographs of the ZnO powder revealed the formation of ZnO flower-like nanostructures. Energy dispersive X-ray (EDS) analysis showed all expected elements. The ZnO powder revealed good optical properties with high absorptions properties in the UV region. The band gap energies increased slightly with an increase in the molar concentration of the zinc acetate and again in synthesizing time. The estimated band energy gaps are 3.24, 3.26 and 3.27 eV for sample synthesized for 10 minutes, 5 minutes and 1 minute, respectively which were lower than that of bulk ZnO (3.37eV). The luminescence intensity was found to decrease with an increase in the zinc acetate mol% and synthesis time, respectively. There was no effect on luminescence band. The photoluminescence measurements reveal a strong emission peak at around 606 nm.