  Recently it has been experimentally shown that a graphene nanoribbon (GNR)
can be obtained by unzipping a carbon nanotube (CNT). This makes it possible to
fabricate all-carbon heterostructures that have a unique interface between a
CNT and a GNR. Here we demonstrate that such a heterojunction may be utilized
to obtain a unique transistor operation. By performing a self-consistent
non-equilibrium Green's function (NEGF) based calculation on an atomistically
defined structure, we show that such a transistor may reduce energy dissipation
below the classical limit while not compromising speed - thus providing an
alternate route towards ultra low-power, high-performance
carbon-heterostructure electronics.
