Characterization of defect type and dislocation density in double oxide heteroepitaxial CeO2/YSZ/Si(001) films

In order to qualitatively and quantitatively analyze the structural defects including the defect types and their concentrations in oxide heteroepitaxial films, a new X-ray rocking-curve width-fitting method was used in the case of double CeO2/YSZ/Si (YSZ = yttria-stabilized ZrO2) films that were prepared by pulsed laser deposition. Two main defect types, angular rotation and oriented curvature, were found in both CeO2 and YSZ. Dislocation densities of CeO2 and YSZ, which were obtained from the angular rotations, are functions of the YSZ thickness. A distinct two-step correlation between dislocation densities of CeO2 and YSZ was found that as the dislocation density of YSZ is higher than 2.4 x 10(11) cm(-2), the dislocation density of CeO2 shows a high sensitivity with that of YSZ compared with the low relativity in lower dislocation density (< 2.4 x 10(11) cm(-2)). In addition, YSZ always has higher dislocation densities and oriented curvatures than CeO2 in each specimen, which can be attributed to the smaller mosaic domain sizes in YSZ than in CeO2 as observed by high-resolution transmission electron microscopy.