  Reproducible current hysteresis is observed in graphene with a back gate
structure in a two-terminal configuration. By applying a back gate bias to tune
the Fermi level, an opposite sequence of switching with the different charge
carriers, holes and electrons, is found. The charging and discharging effect is
proposed to explain this ambipolar bistable hysteretic switching. To confirm
this hypothesis, one-level transport model simulations including charging
effect are performed and the results are consistent with our experimental data.
Methods of improving the ON/OFF ratio of graphene resistive switching are
suggested.
