Unipolar conduction induced by defects in graphene nanowire field effect transistors

We present results on electronic transport in disordered graphene nanowire field effect transistors. We show the emergence of unipolar transport where increasing defects density yield almost an insulating behaviour in n-type graphene whilst showing a metallic behaviour in p-type graphene. It is also shown that the Fermi level is pinned at the Dirac point and the conductivity of n-type graphene is pinned to the minimum conductivity at the Dirac point.