  A typical graphene heterojunction device can be divided into two classical
zones, where the transport is basically diffusive, separated by a "quantum
active region" (e.g., a locally gated region), where the charge carriers are
scattered according to the laws of quantum mechanics.In this paper we derive a
mathematical model of such a device, where the classical regions are described
by drift-diffusion equations and the quantum zone is seen as an interface where
suitable transmission conditions are imposed that take into account the quantum
scattering process. Numerical simulations show good agreement with experimental
data.
