Mobility extraction and quantum capacitance impact in high performance graphene field-effect transistor devices

Abstract

The field-effect mobility of graphene devices is discussed. We argue that the graphene ballistic mean free path, Lball can only be extracted by taking into account both, the electrical characteristics and the channel length dependent mobility. In doing so we find a ballistic mean free path of L ball=300±100nm at room-temperature for a carrier concentration of ∼1012cm-2 and that a substantial series resistance of around 300Ωμm has to be taken into account. Furthermore, we demonstrate first quantum capacitance measurements on single-layer graphene devices.