Synthesis, characterization and antibacterial performance of transparent c-axis oriented Al doped ZnO thin films

Abstract Highly c-axis oriented ZnO thin films with wurtzite structure were grown onto preheated glass using spray pyrolysis technique with varying Al/Zn ratios. The transmittance of visible photons through these films was more than 90% and the color bands seen at an off angle was a clear indication of good quality surface. There was an abrubt change in the surface morphology from mixed nanorods and hexagonal stacks to pyramid like structure on increase in Al/Zn ratios. The shift in optical band gap towards high photon energy on introducing Al in ZnO lattice was regarded as Burstein-Moss effect. Photoluminisce spectroscopy revealed the presence of oxygen vacancies and defects related to Zn. The films were tested for their antibacterial activity against Escherichia Coli bacteria; their efficacy was enhanced on increasing Al/Zn ratio. These antimicrobial coatings with excellent optical properties have potential capability to be used in surgical instruments, protective hospital apparels, medical implants, storage containers, textile, and food packs.