Resistance Switching in Graphene-Insulator-Graphene Structures
Resistive switching in graphene-insulator-graphene structures with graphene used as the material for both top and bottom electrodes is reported. Different dielectric stack configurations are studied to investigate the effect on the switching characteristics. Resistive switching in devices with a stack consisting of TiOx/HfO2 (2 nm/5 nm) requires a high forming voltage of 5 V. By using a stack consisting of TiOx/TiO2 (2 nm/5 nm), the forming voltage can be reduced to 2.5 V, but the reset current increases by almost two orders of magnitude compared to the TiOx/HfO2 case. As a result the TiOx/TiO2 devices are not suitable for low-current operation. Finally, by using an engineered stack of TiOx/Al2O3/TiO2 (1 nm/1 nm/1 nm) both forming-free switching as well as a 10× reduction in operating current compared to conventional TiN/HfTiOx/TiN RRAMs can be obtained.