  We study transport length scales in carbon nanotubes and graphene ribbons
under the influence of Anderson disorder. We present generalized analytical
expressions for the density of states, the elastic mean free path and the
localization length in arbitrarily structured quantum wires. These allow us to
analyze the electrical response over the full energy range, including the
regions around van Hove singularies, traditionally difficult to access by
alternative approaches. Comparing with the results of numerical simulations, we
demonstrate that both the diffusive and the localized regime are well
represented by the analytical approximations over a wide range of the energy
spectrum. The approach works well for both metallic and semiconducting
nanotubes and nanoribbons but breaks down near the edge states of zigzag
ribbons.
