Non-volatile resistive switching memory device based on ZnO-graphene oxide embedded in a polymer matrix fabricated on a flexible PET substrate

This study demonstrates non-volatile resistive switching memory using ZnO nanoparticles (NPs) embedded in GO-PVA composites deposited on pattern Al coated flexible PET substrate. The fabricated Al/ZnO-GO-PVA composite/Al/flexible PET substrate device reveals bipolar non-volatile resistive switching characteristics. This memory device shows a significant reduction in both SET voltages (V-SET) and RESET voltages (V-RESET) as compared to that of control Al/GO-PVA composite/Al/flexible PET substrate device. This reduction of VSET and VRESET in the case of ZnO/GO-PVA nanocomposite is due to the presence of ZnO NPs, resulting in increasing the concentration of oxygen vacancies (holes) into the GO-PVA nanocomposite. It consequently forms the conductive path between Al top electrode (TE) and Al bottom electrode (BE) which is confirmed by using X-ray photoelectron spectroscopy (XPS). This Al/ZnO-GO-PVA composite/Al/flexible PET substrate memory device is measured and tested for the flexibility, stability, retention and endurance by constantly bending the device 50 times from an angle of 180 degree (without bending) to an angle of 90 degree. Surprisingly, the resistances of both high resistance state (HRS) and low resistance state (LRS) reveal no detectable change with different bending angles (50(0), 70(0), 90(0), 120(0), 150(0)) and without bending (180(0)). There is also no noticeable change in the current-voltage resistive switching characteristics even after the memory device is bent from 180(0) to 50(0) angles. This memory device demonstrates good marks in mechanical endurance and flexibility, and indicates the sample is good for bendable non-volatile memory applications.