Structure, composition and electrical properties of YSZ films deposited by ultrasonic spray pyrolysis

Yttria-stabilized zirconia (YSZ) films with different yttria concentrations were prepared by ultrasonic spray pyrolysis on Si substrates at 525 °C, using solutions of zirconium and yttrium acetylacetonates in methanol. The chemical composition, structure and electrical properties of the films were studied by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). XPS measurements show that the Y content in the films increases as the Y precursor in the solution increases. Carbon incorporation was also found in the films, although the concentration of this impurity was reduced as the incorporation of Y increased. XRD spectra show that the Zr_1−xY_xO_2−x/2 polycrystalline films have the cubic phase of ZrO₂ and fully stabilized 8YSZ (8 at.% Y₂O₃ + 92 at.% ZrO₂), and that their lattice constant increases slightly as the Y content increases. The conductivity of all the as-deposited films as a function of temperature, showed an Arrhenius behavior, and with the exception of the film with the maximum Y content, the activation energies were in the range of 0.98–1.11 eV. The ionic conductivity of one of these films was similar to that measured for a pellet made of the 8YSZ standard powder.