  We have studied quantum transport in Graphene Nanoribbon Tunnel Field-Effect
Transistors. Unlike other studies on similar structures, we have included
dissipative processes induced by inelastic electron-phonon scattering and edge
roughness in the nanoribbon self-consistently within a non-equilibrium
transport simulation. Our results show that the dissipative scattering imposes
a limit to the minimum OFF current and a minimum subthreshold swing that can be
obtained even for long channel lengths where direct source-drain tunneling is
inhibited. The edge roughness, in presence of dissipative scattering, somewhat
surprisingly, shows a classical behavior where it mostly reduces the maximum ON
current achievable in this structure.
