(color online) Graphene as built-in selector element to solve sneak leakage path problem.^[19,47] (a) The fabrication process of graphene resistive switching: the green film is TaO_y, the red film is Ta₂O_5−x. (b) The switching characteristics of MLG/TaO_y/Ta₂O_5−x/MLG, which shows linearity. (c) The switching characteristics of MLG/Ta₂O_5−x/TaO_y/MLG, which shows significant nonlinearity. (d) The switching characteristics of bottom electrodes: B1 and B2.