The physical properties and electronic structure of Sm-doped CeO2 (Ce0.90Sm0.10O2-δ) in the thin-film form have been studied. The as-deposited thin film exhibits (111) orientation on an Al2O3(0001) substrate. The lattice constant of the thin film is larger than that of the bulk crystal. The Ce0.90Sm0.10O2-δ thin film has the mixed valence states of Ce4+ and Ce3+. The electrical conductivity of Ce0.90Sm0.10O2-δ thin film in the temperature region from 200 to 700 °C is higher than that of the undoped CeO2 thin film and is independent of the oxygen partial pressure, indicating the occurrence of high oxygen-ion conduction. The valence band consists of the O 2p state hybridized with the Ce 4f state. The 40% Ce3+ (4f1L) state in Ce0.90Sm0.10O2-δ thin film, which was estimated from the resonant photoemission spectra, contributes to the high oxygen-ion conduction and low activation energy.
ASJC Scopus subject areas
- Physics and Astronomy(all)