This paper implements modification of tungsten oxide film using ion implantation and a physical characterization of the film. The film was implanted with nitrogen at energies between 10 keV and 40 keV and ion dose range 1014−1016 cm-2. The surface morphology of the film after implantation has been modified as observed using electron microscopy. The transmittance of the film was found to decrease with increasing implantation energy and ion dose as measured using conventional spectrophotometer. Depth profile of nitrogen was analyzed using Secondary Ion Mass Spectroscopy (SIMS) and found a peak of nitrogen across the depth of the implanted layer. The amount of nitrogen was found to increase with increasing ion dose and energy. From electron diffraction a broader diffraction rings were revealed from both the implanted and un-implanted layers, indicating that the crystalline properties of the tungsten oxide film after ion implantation remains the same.
We report the influence of nitrogen implantation and annealing on the microstructures and photocatalytic properties of a nanostructured titania (TiO2) film. Titania samples were implanted at 40 keV and ion dose range of 1016/cm2 to 4×1016/cm2. From X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses it was found that the anatase phase of titania predominated with small amount of brookite, and the structure was stable at annealing temperatures up to 973 K. The samples showed narrower XRD peaks corresponding to larger mean-grain sizes comparing to the un-implanted titania samples. The SIMS (secondary ion mass spectroscopy) nitrogen depth profile showed a maximum nitrogen concentration at about 70 nm beneath the film surface. The absorption edge of the titania samples as measured using spectrophotometer was found to shift toward longer wavelengths with the increase of ion dose. The experiments of photodegradation of phenol were performed under a UV illumination for the N-implanted titania film which exhibited improved photocatalytic properties with the increase of annealing temperature.
The thermal oxidation of small metallic particles have been studied using infrared spectroscopy. The oxidation has been quantified by measuring the absorption of p-polarized light at 60 degree angle of incidence at the wavelengths around the longitudinal optical (LO) phonon mode of the created oxide. The case presented in this report is nickel rods embedded in alumina (Ni-Al2O3) exposed to temperatures in the range between 300 and 500 degrees Celsius from 1 to 500 hours. The rate of oxidation was found to be somewhat lower than previously reported for large particles and bulk nickel.