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Cerium/vanadium mixed oxide films, designed for applications in electrochemical cells and electrochromic devices, were obtained on glass substrates by the sol-gel process. These nanostructured and porous films were studied by grazing-incidence small-angle X-ray scattering (GISAXS) at the synchrotron ELETTRA in Trieste, Italy. Two-dimensional GISAXS spectra for each film were measured at different grazing angles, starting from slightly below the critical angle. Due to refraction, the X-ray penetration into the film is then reduced to a few nanometers. Therefore, if two-dimensional GISAXS patterns are recorded at angles close to the critical, the surface contribution to the scattering is strongly enhanced. By varying the grazing-incidence angle, the surface and bulk contributions, as different functions of sample to scattering angle orientation, can be clearly distinguished. The GISAXS patterns of the mixed-oxide films with different composition and morphology, obtained by varying the preparation and processing conditions, revealed difference in the surface and bulk characteristics. The quantitative method of interpreting X-ray scattering data is based on the analysis of the scattering curve, which generally shows the dependence of the scattering intensity on the scattering wave vector. We extracted one-dimensional scattering curves from the two-dimensional GISAXS intensity maps, showing the dependence of the scattering intensity on different components of the wave vector in the scattering plane. These extractions - "cuts" in different directions (for example: vertical, diagonal, horizontal) - enable a specific film depth nanostructural profiling. Considering the sensitivity of a particular cut to a particular group of the scattering particles in film, information about surface and bulk film characteristics can be filled up. The size of the scattering particles, their spatial orientation, shape and organization can be discussed for different film regions, from its surface to the substrate. |