Optical properties of ceria–zirconia epitaxial films grown from chemical solutions

Epitaxial thin films of ceria–zirconia solid solutions were grown on yttria-stabilized zirconia (YSZ) substrates by chemical solution deposition. Characterization by X-ray diffraction, atomic force microscopy and variable angle spectroscopic ellipsometry show that high-quality, epitaxial, high density films, with a thickness in the range of 20–27 nm were obtained. Compositional dependence of the film optical constants (n and k) was determined from ellipsometry measurements. It was found that the optical properties for the mixed-oxide films smoothly vary between the values for the pure oxides and are best described by means of a Tauc–Lorentz (TL) model. Moreover, we found that the parameters of the TL model have a linear dependence on the cerium concentration. The obtained results can serve as a database for the thickness, composition and porosity characterization of CexZr1−xO2 thin films.