Double-gated graphene-based devices

We discuss transport through double-gated single-and few-layer graphene devices.This kind of device configuration has been used to investigate the modulation of the energy band structure through the application of an external perpendicular electric field, a unique property of few-layer graphene systems.Here we discuss technological details that are important for the fabrication of top-gated structures, based on electron-gun evaporation of SiO 2 .We perform a statistical study that demonstrates how-contrary to expectations-the breakdown field of electron-gun evaporated thin SiO 2 films is comparable to that of thermally grown oxide layers.We find that a high breakdown field can be achieved in evaporated SiO 2 only if the oxide deposition is directly followed by metallization of the top electrodes, without exposure of the SiO 2 layer to air.