The impressive properties of graphene such as the linear energy dispersion relation, room-temperature mobility as high as 15 000 cm2/V.s, and current densities in excess of 2 A/mm range – or even 10 A/mm for nanoribbons – make it an attractive candidate for electronic devices of the future.
This work explores whether graphene fulfills the promises raised by the extraordinary material properties. First, realistic expectations of large area and nanoscale graphene devices are examined. Fabrication and electrical measurements of 2D graphene devices lead to the verification of the predicted T^2 dependence of the intrinsic carrier concentration in graphene. A suitable model allows the extraction of the mobility of carriers at the Dirac point, a quantity of great ambiguity in the literature.
The opening of bandgaps in graphene nanoribbons (GNRs) by quantum confinement holds promise for digital electronic device applications. The fabrication, device performance, and modeling of low bandgap GNR FETs are presented. For substantial current modulation at room-temperature, sub-10 nm GNR widths are required – and is challenging. Process limitations lead to the utilization of a new e-beam lithography resist (HSQ) and to the switch to epitaxial graphene on SiC substrates. The measurements of the GNR FETs confirm larger than ~0.1 eV bandgap in ~10 nm wide ribbons. These results have been replicated on FETs formed from CVD grown graphene.