Electrical bistabilities behaviour of all-solution-processed non-volatile memories based on graphene quantum dots embedded in graphene oxide layers

This study demonstrates the feasibility of all-solution-processed mean to fabricate carbon-based non-volatile memory (NVM). The NVM devices were fabricated on polyethylene terephthalate (PET) substrate using spin-coating and spray-coating techniques in the structure of silver nanowires (AgNWs)/graphene oxide (GO)/graphene quantum dots (GQDs)/graphene oxide (GO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/PET. PEDOT:PSS was used as the bottom conductive layer and deposited by spin-coating method. GQDs were used as a charge trapping site in the structure and embedded in the two GO insulator layers. The AgNW metal electrode was formed on top of GO/GQDs/GO/PEDOT:PSS by the spray-coating method. The overall smooth surface morphology of the spray-coated films serves as good contact with the top metal electrode. The electrical characterization of the fabricated device shows the bistable current states with the ON/OFF ratio of 10⁵. The NVM device can be programmed and erased multiple times. Various conduction mechanisms were proposed to describe the charge trapping process in GQD based on the obtained current–voltage measurement.