Influence of multiple interfaces on oxygen ionic conductivity in gadolinia-doped single crystal oxide electrolyte multi-layer nano films

Single-crystal multi-layered thin films of pure and gadolinia-doped ceria and zirconia were heteroepitaxially grown on sapphire (0001) substrates using molecular beam epitaxy. The growth of these films was monitored using in-situ reflection high-energy electron diffraction (RHEED). In addition, the ex-situ characterization techniques including X-ray diffraction (XRD), and Rutherford backscattering spectrometry (RBS) along with ion channeling were used to further characterize these films. The electrical conductivity in these films was measured using a four-probe van der Pauw technique. Oxygen ionic conductivity at low temperatures appeared to be higher in the four-layer film compared to two-layer film.