Resistive hysteresis and diodelike behavior of BiFeO₃ /ZnO heterostructure

Bilayered BiFeO₃ /ZnO thin films, which were grown on the SrRuO₃ -buffered MgO(100) substrate by off-axis radio frequency magnetron sputtering, are investigated for their current-voltage relationships at varying voltages and temperatures. A resistive hysteresis and a diodelike behavior are observed for the bilayered BiFeO₃ /ZnO thin films. The resistive hysteresis and the rectification ratio are enhanced with increasing electrical field and temperature. The observed behavior arises from the interfacial depletion layer and ferroelectric switching, where the charge coupling between the semiconducting ZnO and the ferroelectric BiFeO₃ layers occurs.