Effect of Post Annealing on Antibacterial Activity of Zno thin Films Prepared by Modified Silar Technique

Zinc oxide (ZnO) thin films were prepared by modified Successive Ionic Layer Adsorption and Reaction (SILAR) method. The optical, structural and antibacterial properties of the prepared ZnO films were analyzed as a function of its annealing temperature lying in the range of 250oC to 450oC. Optical properties were studied using UV-Visible spectroscopy and Photoluminescence spectroscopy (PLS). Optical absorption spectra exhibited blue shift when compared to the bulk value and also the presence of interstitial Zn+ ion defect and oxygen ion vacancy were confirmed in the prepared ZnO thin films by PL studies. X-Ray Diffraction (XRD) pattern revealed the formation of hexagonal phase ZnO and the intensity of the film were found to increase with increase in annealing temperature. Field Emission Scanning Electron Microscope (FESEM) images show the presence of flower like structure and pinhole free film throughout the substrate. Antibacterial activity against Escherichia coli (E.coli) was highly dependent on the presence of interstitial Zn+ ions and for Staphylococcus aureus (S.aureus) it was dependent on oxygen vacancy in the films. keywords: ZnO Thin films; PL; XRD; FESEM; Antibacterial activity.