Electronic transport properties of top-gated epitaxial-graphene nanoribbon field-effect transistors on SiC wafers

Top-gated epitaxial-graphene nanoribbon (GNR) field-effect transistors on SiC wafers were fabricated and characterized at room temperature. The devices exhibited extremely high current densities (∼10 000 mA/mm) due to the combined advantages of the one-dimensionality of GNRs and the SiC substrate. These advantages included good heat dissipation as well as the high optical phonon energy of the GNRs and SiC substrate. An analytical model explains the measured family of I_D–V_DS curves with a pronounced ‘kink’ at a high electric field. The effective carrier mobility as a function of the channel length was extracted from both the I_D–V_DS modeling and the maximum transconductance from the I_D–V_GS curve. The effective mobility decreased for small channel lengths (<1 μm), exhibiting ballistic or quasiballistic transport properties.