Electric Field Effect in Epitaxial Graphene Devices

The electric field effect has been observed on epitaxial graphene multilayers grown on SiC substrates by thermal decomposition of SiC. Carriers mobilities up to 2.5$\times $10$^{4}$cm$^{2}$/Vs have been measured. Both side-gated and top-gated graphene field effect transistors (FETs) have been fabricated using standard semiconductor processes on both the Si and the C face of the SiC substrates. In side-gated FETs, the gates are located on both sides of narrow graphene ribbons; source-drain resistances decrease by several percent with a gate bias of several volts. For top-gated FETs the resistance swing reaches a factor of 25. At the gate voltage corresponding to the maximum source-drain resistance, the Hall voltage changes sign indicating a transition from hole- to electron- carried transport, consistent with the graphene band structure. These results indicate the potential of epitaxial graphene as a platform for large-scale graphene based electronics.