Enhancing the antibacterial properties of zinc sulfide thin films by substrate patterning

To investigate the porosity and substrate effects on the antibacterial properties of ZnS thin films, sculptured structures were considered. Two types of uncoated glass and primary coated glass were used as different substrates. Since the porosity percentage is dependent on the shadow of grains, spiral structures with different numbers of pitches were formed on the different substrates. The cross-section and morphology of the samples were investigated by means of FESEM images. To evaluate the antibacterial properties of the samples under light irradiation, the absorption spectra of the structures at different wavelengths were obtained and investigated. The results showed that most adsorption of structures occurs at wavelengths less than 400 nm. Finally, antibacterial properties of this thin film were investigated in two cases of without light and with light irradiation, for two types of Escherichia coli and Staphylococcus aureus bacteria. The results showed that the structures with higher porosity have better antibacterial properties. The results also showed that light radiation increases the antibacterial properties of structures.