Multilevel resistive switching in graphene oxide-multiferroic thin-film-based bilayer RRAM device by interfacial oxygen vacancy engineering

This work demonstrates the graphene oxide (GO) RRAM exhibiting low-power, low-voltage multilevel resistive switching when clamped to an oxygen vacancy rich bismuth ferrite (BFO) thin film. The GO/BFO structure also shows stable endurance characteristics with a larger memory window due to the accumulation of excess oxygen vacancies. The conduction process in pristine GO does not suffer larger distortion when it is stacked to BFO and follows Ohmic and trap-assisted space charge limited current conduction mechanism. In GO RRAM, Ag+ ion-induced conducting filament is primarily responsible for the switching process, while oxygen vacancies are dominating in bilayer device. The GO/BFO exhibits intermediate resistive states during the RESET process due to multiple breakdowns of conducting paths. At least a 4-bit multistate data storage configuration is demonstrated by tuning the pulse-amplitude of RESET from 2 to 5 V at a constant SET voltage of ? 3 V. Thereafter, a 3-bit multilevel storage device can be configure.