Grazing-incidence small-angle X-ray scattering and reflectivity on nanostructured oxide films

Titanium dioxide, cerium dioxide, new Ce/Sn oxide films, vanadium oxide and new V/Ce oxide films on glass substrate were obtained by sol–gel process. The morphology and phase transitions of these nanostructured and porous films was studied by grazing-incidence small-angle X-ray scattering (GISAXS) at the ELETTRA synchrotron (Trieste, Italy). Beside the technological value of determining morphology of these films, a fundamental issue of origin of forming crystalline nanoparticles from amorphous phase is tackled by observing amorphous interphase in structural phase transition anatase–rutile and transition amorphous–crystalline in vanadium oxide. The average grain radius 〈R〉 obtained by GISAXS varied with the annealing temperature, atmospheres (H2, O2 and N2), the number of dips and the layer thickness. Layer structure in V/Ce oxides was revealed by grazing-incidence X-ray reflectivity (GIXR) method. The average grain radius 〈R〉, obtained by GISAXS was correlated with layer thickness. The specific surface area of these films was also determined and generally varied from 0.1 to 4 nm−1.