  Graphene nanoribbon (GNR) field-effect transistors (FETs) with widths down to
12 nm have been fabricated by electron beam lithography using a wafer-scale
chemical vapor deposition (CVD) process to form the graphene. The GNR FETs show
drain-current modulation of approximately 10 at 300 K, increasing to nearly 106
at 4 K. The strong temperature dependence of the minimum current indicates the
opening of a bandgap for CVD-grown GNR-FETs. The extracted bandgap is estimated
to be around 0.1 eV by differential conductance methods. This work highlights
the development of CVD-grown large-area graphene and demonstrates the opening
of a bandgap in nanoribbon transistors.
