CeO 2 thin films were deposited on silicon and silicon nitride substrates by magnetron sputtering at room temperature and annealed at 400 and 600 °C in air and vacuum. Interaction between deposited CeO 2 and Si in CeO 2 /Si and CeO 2 /Si 3 N 4 systems was investigated by XPS. The results show that Ce is present as both Ce 4+ and Ce 3+ oxidation states in CeO 2 film deposited on Si substrate, whereas Ce 4+ is the main species in as-deposited CeO 2 /Si 3 N 4 film. Detailed analyses of Ce3d, Si2p and O1s core level spectra demonstrate that Ce 2 O 3 and SiO x or cerium silicate type of species are formed at the interface of CeO 2 and Si. Concentrations of Ce 3+ species increase drastically in CeO 2 /Si thin films after annealing at 400 °C in vacuum due to enhanced interfacial reaction. On the other hand, interfacial reaction between CeO 2 and Si 3 N 4 substrate is limited in as-deposited as well as 600 °C heat treated films.

No abstract

No abstract

No abstract

Vanadium oxide thin films were grown on both quartz and Si(111) substrates utilizing pulsed RF magnetron sputtering technique at room temperature with RF power at 100 W to 700 W. The corresponding thicknesses of the films were increased from 27.5 nm to 243 nm and 21 nm to 211 nm as RF power increased from 100 W to 700 W for quartz and silicon substrates, respectively. X-ray diffraction and field emission scanning electron microscopy were carried out to investigate the phase and surface morphology of the deposited films. Electronic structure and vanadium oxidation states of the deposited films were investigated thoroughly by X-ray photoelectron spectroscopy. As-grown films show stoichiometric vanadium oxide only where vanadium is in V 5+ and V 4+ states. Phase transition of vanadium oxide films were investigated by differential scanning calorimetric technique. The reversible i.e. smart transition was observed in the region from 337 °C to 343 °C. Average hemispherical emittance of the deposited vanadium oxide films was evaluated by an emissometer in the wavelength range of 3 µm to 30 µm. The sheet resistance of the deposited films was measured by two-probe method and data were in the range of 10 6 to 10 5 Ω/square. Optical properties of the films such as solar transmittance, solar reflectance and solar absorptance as well as optical constants e.g. optical band gap were also evaluated. Finally, mechanical properties such as nanohardness and Young's modulus at microstructural length scale were evaluated employing nanoindentation technique with continuous stiffness mode.