Annealing temperature effect on the surface properties and antimicrobial activity of SnSe thin films

Abstract

In this study, tin selenide thin films with various atomic ratios were fabricated using the RF magnetron co-sputtering method and annealed at different temperatures. In order to observe the structural and chemical properties of the thin films, various characterization tools and methods such as atomic force microscope (AFM), scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy, Kelvin probe, and antimicrobial test against Escherichia coli were performed. SEM and AFM images showed that the surface morphology of the thin films changed at 573 K. Additionally, the phase changed from amorphous to orthorhombic SnO2 at high temperature, which was confirmed by XRD results. XPS results confirmed SnSe thin films was oxidized and Se evaporated as the annealing temperature increased. The work function of thin films with higher contents of Sn than Se were increased from 5.23 to 5.68 eV as the annealing temperature increased. On the other hand, the work function of thin films with higher Se content than Sn decreased from 5.86 to 5.44 eV. Antimicrobial testing revealed that the SnSe thin films exhibit a stronger effect compared to pure Sn and Se thin films.