Tunable Power Switching in Nonvolatile Flexible Memory Devices Based on Graphene Oxide Embedded with ZnO Nanorods

The growing demand for portable and bendable nonvolatile memory systems has motivated extensive research in the field of flexible resistive random access memory (RRAM) devices. This study investigated the resistive switching and flexibility behavior of zinc oxide nanorods (ZNs) incorporated graphene oxide (GO) sheets. GOZNs-based RRAM devices having top metal aluminum electrodes were fabricated on flexible indium tin oxide (ITO) coated polyethylene terephthalate (ITOPET) substrate. The devices having the structure Al/GOZNs/ITOPET showed typical bipolar resistive switching characteristics with switching voltages lower than those of Al/GO/ITOPET devices. The significant (similar to 50%) decrement in operating voltages in the case of GOZNs-based RRAM was attributed to enhanced concentration of oxygen vacancies into the GO matrix due to the incorporation of ZNs, which was supported by X-ray photoelectron spectroscopy studies. These memory devices showed repeatable and reliable switching characteristics having an on/off ratio of similar to 100, lower switching voltages, good retention properties up to similar to 10(4) s, and endurance performance over 200 cycles. The resistance ratio of the GOZNs RRAM devices was maintained almost constant even for the extreme bending radius of 4 mm and mechanical flexing test over 10(3) cycles, indicating excellent flexibility. These GOZNs-based RRAM devices showed great potential for use in future flexible nonvolatile memory devices.