The structure and electron energy loss near edge structure of tungsten oxide thin films prepared by pulsed cathodic arc deposition and plasma-assisted pulsed magnetron sputtering

The microstructure and energy-loss near-edge structure (ELNES) of pulsed cathodic arc and pulsed magnetron sputtered WO₃ thin films were investigated. It was found that the cathodic arc deposited material consisted of the α-WO₃ phase with a high degree of crystallinity. In contrast, the magnetron sputtered material was highly disordered making it difficult to determine its phase. A self-consistent real space multiple scattering approach was used to calculate the NES of the various phases of WO₃. Each phase was found to exhibit a unique NES allowing different phases of WO₃ to be identified. The real space approach also allowed the origin of the main features in the NES to be investigated as the cluster size increased. The calculated NES for the room temperature γ-WO₃ was found to compare well to previous X-ray absorption spectra and to NES obtained by full-potential band structure calculation.