Coexistence of bipolar and unipolar resistive switching behavior in a Pt/TiO2/Pt stack

Bipolar resistive switching (BRS) as well as unipolar resistive switching (URS) behaviors in Pt/27 nm thick TiO2/Pt stacks were investigated. Depending on the current compliance during the electroforming process, either BRS or URS was observed. With a lower current compliance (< 0.1 mA) during electroforming, asymmetric current-voltage curves showing BRS were observed in the voltage range -1.6 to +1.1 V, while with a higher current compliance (1-10 mA) URS behavior was observed. Furthermore, the permanent transition from BRS to URS was investigated by applying a voltage with a higher current compliance (similar to 3 mA)