Orientation-dependent potential barriers in case of epitaxial $Pt–BiFeO3–SrRuO3$ capacitors

The leakage current in epitaxial $BiFeO3$ capacitors with bottom $SrRuO3$ and top Pt electrodes, grown by pulsed laser deposition on $SrTiO3$ (100), $SrTiO3$ (110), and $SrTiO3$ (111) substrates, is investigated by current-voltage $(I-V)$ measurements in the 100–300 K temperature range. It is found that the leakage current is interface-limited and strongly dependent on the orientation of the substrate. The potential barriers at the electrode interfaces are estimated to about 0.6, 0.77, and 0.93 eV for the (100), (110), and (111) orientations, respectively.