(color online) Graphene-based 3D RRAM.^[46] (a) The schematic of graphene-based 3D RRAM in vertical crossbar architecture. (b) The set/reset voltage distribution of Pt-RRAM and GS-RRAM after 50 cycles of switching. (d) Schematic of Pt-RRAM mechanism. (e) Schematic of GS-RRAM mechanism. (f) Changes of 2D peaks intensity of the graphene electrode during the switching process.