Evolution of resistive switching and its ionic models in Pt/Nb-doped SrTiO₃ junctions

Charge-trapping or ionic mechanisms of the resistive switching (RS) at metal/Nb-doped SrTiO₃ (NSTO) interfaces are still unclear. Here, the electrical properties and RS evolution at Pt/NSTO interfaces are investigated. A volatile RS in the fresh junctions complies with Schottky theory involving an interfacial layer and electrically dependent permittivity. The RS is interpreted by a redox-reaction modulated barrier model. A nonvolatile RS emerges and evolves with increasing the forward voltage. I – V and C – V characteristics imply different conductive filament (CF) configurations in high and low resistance states. An in-barrier ionic CF model is established for the nonvolatile RS. The coherent ionic models are beneficial for understanding the interfacial role in RS and for regulating RS characteristics or realizing high quality metal/oxide diodes. (paper)