Ultraviolet irradiation-controlled memory effect in graphene field-effect transistors.

Control of graphene memory devices using photons, via control of the charge-transfer process, is demonstrated by employing gate-voltage pulses to program/erase the memory elements. The hysteresis in the conductance-gate voltage-dependence of graphene field-effect transistors on a SiO2 substrate can be greatly enlarged by ultraviolet irradiation in both air and vacuum. An enhanced charge transfer between graphene and its surroundings, induced by ultraviolet illumination, is proposed.