Significantly-enhanced Stabilities in Flexible Hybrid Organic-Inorganic Perovskite Resistive Random Access Memories by Employing Multilayer Graphene Transparent Conductive Electrodes

Despite several reports on perovskite resistive random access memories (RRAMs), most of them are based on transparent conductive oxide electrodes, not suitable for high flexibility. We first employ multilayer-graphene (MLG) transparent conductive electrodes (TCEs) for flexible hybrid organic-inorganic perovskite RRAMs, showing reversible bipolar resistive switching behaviors with about 0.68 and -0.5 V as set and reset bias voltages, respectively. The low-resistance state (LRS) and high-resistance state (HRS) of the RRAMs are almost constant even by data retention, switching, and bending for >10(4) s, > 500 cycles, and > 1000 cycles, respectively. The I-V curve at the HRS during the set process is consistent with the Ohm's law for small voltages, but is well described by the space-charge-limited conduction mechanism for large voltages. The Ohmic conduction is also observed at the LRS during the set process. These behaviors are similarly repeated during the reset process, and well explained based on defect migration and charge trapping. These results suggest that perovskite RRAMs can be remarkably stable enough for practical applications by employing MLG TCEs.