Photocurrent in BiFeO3 thin films

Abstract

The study of switching and polarization of the domains in coplanar electrode design structured BiFeO3 (BFO) thin films reaped very interesting similarities with widely studied stacked heterostructures. High polarization values (~90-100µC/cm2) and low coercive fields (50-100kV/cm) could be obtained indicating high quality of epitaxial films. Additionally, miscut angles play similar roles in domain pinning and further study of in-plane (IP) polarization directions employing the use of piezoresponse force microscopy confirmed the existence of 4 variants. However, coercive field values obtained had led to the discovery of deviations in the scaling law correlating thickness with coercive field and could re-open the possibility of additional study of this correlation. In addition, the preliminary observation of fascinating relaxation patterns showed potential in revealing domain growth through a reverse fashion. Current-voltage measurements indicated photocurrent generation in the order of ~10-13A which remained out of range of the equipment capability. Further work to study the effects of illumination as well as polarization effects on photocurrents had been proposed.