Abstract:
Titanium oxynitride (TiOxNy ) thin films were deposited on the silicon wafer and microscope slide substrates by a reactive DC magnetron sputtering method, divided into two sets of experiments. In the first set of experiments, the thin films were prepared based on a constant flow rate of N2 to obtain the golden-TiN thin film, while the O2 flow rate was varied from 0 -2.0 sccm. In the second set, the thin films were coated based on a constant flow rate of O2 to obtain the rutile-titanium dioxide (TiO2 ) thin film, the N2 flow rate was varied from 0 -10 sccm. Some of the specimens were annealed at 500 °C in air ambient for 60 min. The crystal structure of the thin films was investigated using X-ray diffraction (XRD) and Raman spectroscopy techniques. The cross-sectional, surface morphology and thickness of the thin films were measured by a field emission scanning electron microscope (FE-SEM). The elemental composition was analyzed by X-ray photoelectron spectroscopy (XPS). The optical properties were examined by UV-VIS spectrophotometer. The results of the first set showed that an as-deposited film with O/N of 0.04 exhibited a face-centered cubic structure of TiOxNy similar to golden-TiN. When the O/N increased, the thin films became amorphous then changed to rutile-TiO2 when the O/N ratio was 0.20 and more. As a result of the annealed thin films, it was found that the TiN thin film showed slight oxidation, while the amorphous films have been changed to the anatase-rutile mixed phase. The results of the second set revealed that all samples were amorphous except an as-deposited film without N2 feed represents the single crystal (110) of rutile-TiO2 structure. After being annealed, the amorphous films changed to the crystalline of the anatase-rutile mixture films. In this research, the photocatalytic activity test by MB degradation under LED irradiation of 120 min provided the highest degradation rate of 71.67% with the pseudo-first-order reaction rate constant of 8.93×10-3 min-1 for the thin film deposited at the O/N ratio of 0.13 of the second set.