  The performance limits of the multilayer graphene nanoribbon (GNR)
field-effect transistor (FET) are assessed and compared to those of monolayer
GNR FET and carbon nanotube (CNT) FET. The results show that with a thin high-k
gate insulator and reduced interlayer coupling, multilayer GNR FET can
significantly outperform its CNT counterpart with a similar gate and bandgap in
terms of the ballistic on-current. In the presence of optical phonon
scattering, which has a short mean free path in the graphene-derived
nanostructures, the advantage of the multilayer GNRFET is even more
significant. The simulation results indicate multilayer GNRs with
incommensurate non-AB stacking and weak interlayer coupling are the best
candidate for high performance GNR FETs.
