Since discuss the onset of weak and

Since the exploration of fullerenes (C60),
carbon-based materials have the subject of intense research, which led to the exploration
of carbon nanotubes and the fabrication of individual one-atom thick graphene
layers. These systems share a similar underlying
electronic structure, whose exact details depend on confi nement effects,
crucial differences emerge when disorder becomes into play. The transport
properties of these materials considered with particular affirmation on the
case of graphene nanoribbons which the presence of the edges exposes the system
to further sources of disorder. The electronic transport properties of boron
doped armchair ribbons shown, by means of ab initio calculations, to depend
strongly on the symmetry of the ribbon, as B-induced potentials that preserve
the parity of the wavefunctions do not affect the conductance of odd indexed
ribbons at low energies. Scattering investigete by certain defects might be repressed,
provided that the defects preserve the underlying symmetric geometry of the
ribbon. Transport properties in graphene-based materials also turn out to be
strongly affected by disorder, which can originate from impurities such as charges
trapped in the oxide, chemical impurities, etc., topological defects such as vacancies,
edge disorder…, or long range deformation modes (ripples) in 2-D graphene. The
analytical expressions for the elastic mean free path of carbon nanotubes and
graphene nanoribbons, and discuss the onset of weak and strong localization
regimes, which are genuinely dependent on the transport dimensionality. The
effects of edge disorder and roughness for graphene nanoribbons consider in
relation to their armchair or zigzag orientation.
The study with Anderson
disorder indicates that even in the strongest case of short range scattering
potential (with possible short range potential fluctuations as large as 1 eV),
the computed 2-D localization lengths remain in the range of several hundred
nanometers to microns. The results show to observe weak and strong localization
regimes, the presence of edges as well as a reduced lateral size are essential
factors. Nanoribbons with zigzag
symmetries are even more spectacularly sensitive to disorder owing to the edge
state-driven lower transport dimensionality. In contrast, for charge carrier
energies lying in the higher energy subbands, the properties of nanotubes and
ribbons provied similar features, with strong energy dependence of elastic mean
free paths and localization phenomena.