Nanostructure and strain analysis of CeO2/YSZ strained superlattice

The nanostructure and the strain fields in the superlattice [CeO2/YSZ]5 fabricated on a SiO2/Si(001) substrate were investigated macroscopically and nanoscopically using XRD and HRTEM with geometric phase analysis (GPA) and related methods. The XRD analyses elucidated that the out-of-plane lattice parameter of CeO2 and YSZ layers was relaxed. However, the in-plane lattice parameter was almost identical. Results of HRTEM and related analyses revealed that CeO2 and YSZ layers formed a superlattice structure. Results showed that the superlattice has some defects, such as misorientation, varied thickness of CeO2 and YSZ layers, varied artificial periodicity, and interface roughness. However, the out-of-plane lattice parameter had periodicity corresponding to the superlattice structure. The in-plane lattice parameter was also equal to the local deviation. Therefore, the strain effect in the superlattice persisted to some degree.