The physics of few-layer graphene under strong surface doping via electrochemical gating

The temperature dependence of electric transport properties of single-layer and few-layer graphene (FLG) at large surface charge doping is of great interest both for the study of the scattering processes dominating the conductivity at different temperatures and in view of the theoretically predicted possibility to reach the superconducting state in such extreme conditions [1, 2]. Here we present the results of electric transport measurements in 3-, 4- and 5-layer exfoliated graphene samples with Bernal stacking (3LG, 4LG and 5LG in the following) down to 3.5 K and up to an induced surface charge density that ranges from about 5·10^14 cm^-2 in 3LG to about 7·10^14 cm^-2 in 5LG. This huge surface charge doping was obtained by using a novel polymer electrolyte solution (PES) of improved efficiency for the electrochemical gating [3].