  The operation of a digital logic inverter consisting of one p- and one n-type
graphene transistor integrated on the same sheet of monolayer graphene is
demonstrated. The type of one of the transistors was inverted by moving its
Dirac point to lower gate voltages via selective electrical annealing. Boolean
inversion is obtained by operating the transistors between their Dirac points.
The fabricated inverter represents an important step towards the development of
digital integrated circuits on graphene.
