Large rectifying leakage current in Pt/BaTiO3/Nb:SrTiO3/Pt structure

20-nm-thickness epitaxial BaTiO3 (BTO) thin films were prepared on the Nb-doped SrTiO3 single-crystal substrates by RF magnetron sputtering technology. The rectifying characteristic current-voltage curves were observed and was discussed using the Schottky barrier model taking into account the movement of oxygen vacancies. The leakage current mechanisms were interpreted by the Schottky emission and Poole-Frenkel emission near the Pt/BTO interface at lower bias and higher bias, respectively.