  Sub-10nm wide graphene nanoribbon field-effect transistors (GNRFETs) are
studied systematically. All sub-10nm GNRs afforded semiconducting FETs without
exception, with Ion/Ioff ratio up to 10^6 and on-state current density as high
as ~2000uA/um. We estimated carrier mobility ~200cm2/Vs and scattering mean
free path ~10nm in sub-10nm GNRs. Scattering mechanisms by edges, acoustic
phonon and defects are discussed. The sub-10nm GNRFETs are comparable to small
diameter (d<=~1.2nm) carbon nanotube FETs with Pd contacts in on-state current
density and Ion/Ioff ratio, but have the advantage of producing
all-semiconducting devices.
