A BaTiO3−δ thin film with oxygen vacancies was prepared on a Pt=Al2O3 (0001) substrate by RF magnetron sputtering. The prepared thin film was preferentially grown in the  direction. The BaTiO3−δ thin film with a reduced interplanar distance (d111) exhibited the Ti3+ valence state of 4.4%, which is closely related to concentration of oxygen vacancies. The activation energy estimated from the Arrhenius plot of the electrical conductivity was approximately 61 meV. The electrical conductivity of ∼10−5 S=cm at room temperature did not depend on the oxygen gas partial pressure. The photoemission spectra exhibited the O-H bond peak and donor state near the Fermi level. These results indicate that the BaTiO3−δ=Pt=Al2O3 (0001) thin film has surface electron-proton mixed conduction at room temperature.
ASJC Scopus subject areas
- General Physics and Astronomy