Influence of La and Mn dopants on the current-voltage characteristics of BiFeO3/ZnO heterojunction

We report the influence of La and Mn dopants on the current-voltage characteristics of BiFeO3/ZnO heterojunction. The increased current densities (J) and enhanced diodelike behavior are clearly observed in (Bi0.95La0.05)FeO3/ZnO and Bi(Fe0.95Mn0.05)O-3/ZnO compared to BiFeO3/ZnO. The diodelike behavior is found to arise from the polarization switching of the ferroelectric layer and the resulting interfacial charge distribution. A ferroelectric-semiconductor (FS) model is proposed to understand the physics origins of the La and Mn dopants induced current density and diodelike behavior enhancement. Further studies into the conduction mechanisms reveal that the dominant conduction mechanisms in low electric fields vary with La and Mn dopants, while they remain the same in high electric fields. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699033]