  We investigate the role of various structural nonidealities on the
performance of armchair-edge graphene nanoribbon field effect transistors
(GNRFETs). Our results show that edge roughness dilutes the chirality
dependence often predicted by theory but absent experimentally. Instead, GNRs
are classifiable into wide (semi-metallic) vs narrow (semiconducting) strips,
defining thereby the building blocks for wide-narrow-wide all-graphene devices
and interconnects.
  Small bandgaps limit drain bias at the expense of band-to-band tunneling in
GNRFETs. We outline the relation between device performance metrics and
non-idealities such as width modulation, width dislocations and surface step,
and non-ideality parameters such as roughness amplitude and correlation length.
