Impact of aluminium on ZnO thin films for antimicrobial activity

Abstract

Thin films of pure zinc oxide (ZnO) and aluminium (Al) doped ZnO were deposited by two step SILAR technique. Pure and Al (1%, 3%, 5%) doped ZnO thin film’s structural, morphology and optical properties were analyzed. Diffraction peaks of all the samples were indexed to hexagonal Wurtizite structure. The crystallite size, lattice parameters, dislocation density and microstrain were calculated for the prepared thin films. Morphology study using FESEM shows spherical shaped structure of pure ZnO and hexagonal faced rod like structure for Al doped ZnO thin films. The UV-vis absorption spectrum for the thin films was also studied. There is decrease in bandgap as the Al doping ratio increases from 1% to 5%. Photoluminescence studies confirmed that oxygen ion vacancy and interstitial Zn+ ion were present. The maximum zone of inhibition was studied against the Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria by agar diffusion method. Significant antimicrobial results were seen in pure and Al doped ZnO. Aluminium doped ZnO shows more antimicrobial activity over pure ZnO.