One-Step All-Solution-Based Au-GO Core-Shell Nanosphere Active Layers in Nonvolatile ReRAM Devices

Nonvolatile resistive random-access memory devices based on graphene-oxide-wrapped gold nanospheres (AuNS@GO) are fabricated following a one-step room-temperature solution-process approach reported herein for the first time. The effect of the thickness of the GO layer (2, 5, and 7 nm) and the size of the synthesized AuNS (15 and 55 nm) are inspected. Reliable bistable switching is observed in the devices made from a flexible substrate and incorporating 5 and 7 nm thick GO-wrapped AuNS, sandwiched between two metal electrodes. Current-voltage measurements show bipolar switching behavior with an ON/OFF ratio of 10(3) and relatively low operating voltage (-2.5 V). The aforementioned devices unveil remarkable robustness over 100 endurance cycles and a retention of 10(3) s. Conversely, a 2 nm thick GO layer is shown to be insufficient to allow current passage from the bottom to the top electrodes. The resistive switching mechanism is demonstrated by space charge trapped limited current due to the AuNS in AuNS@GO matrix. The proposed device and methodology herein applied are expected to be attractive candidates for future generation flexible memory devices.