  Conventional field effect transistor operation in graphene is limited by its
zero gap and minimum quantum conductivity. In this work, we report on
controlled electrochemical modification of graphene such that its conductance
changes by more than six orders of magnitude, which enables reversible bipolar
switching devices. The effect is explained by a chemical reaction of graphene
with hydrogen (H+) and hydroxyl (OH-), which are catalytically generated from
water molecules in the sub-stochiometric silicon oxide gate dielectric. The
reactive species attach to graphene making it nonconductive but the process can
subsequently be reversed by short current pulses that cause rapid local
annealing. We believe that the demonstrated electrochemical field effect
devices are viable candidates for future logic circuits, non-volatile memories
and novel neuromorphic processing concepts.
