Electro-optical dual modulation on resistive switching behavior in BaTiO3/BiFeO3/TiO2 heterojunction**Project supported by the Scientific Research Program of Hunan Provincial Education Department, China (Grant No. 18C0232) and the International Cooperative Extension Program of Changsha University of Science and Technology, China (Grant No. 2019IC35).

Abstract

The novel BaTiO3/BiFeO3/TiO2 multilayer heterojunction is prepared on a fluorine-doped tinoxide (FTO) substrate by the sol–gel method. The results indicate that the Pt/BaTiO3/BiFeO3/TiO2/FTO heterojunction exhibits stable bipolar resistive switching characteristic, good retention performance, and reversal characteristic. Under different pulse voltages and light fields, four stable resistance states can also be realized. The analysis shows that the main conduction mechanism of the resistive switching characteristic of the heterojunction is space charge limited current (SCLC) effect. After the comprehensive analysis of the band diagram and the P–E ferroelectric property of the multilayer heterojunction, we can deduce that the SCLC is formed by the effect of the oxygen vacancy which is controlled by ferroelectric polarization-modulated change of interfacial barrier. And the effective photo-generated carrier also plays a regulatory role in resistance state (RS), which is formed by the double ferroelectric layer BaTiO3/BiFeO3 under different light fields. This research is of potential application values for developing the multi-state non-volatile resistance random access memory (RRAM) devices based on ferroelectric materials.