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Smart Materials & Structures Conference
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Journal of Material Sciences and Engineering| ISSN: 2169-0022 | GDCSM-2018 | Volume: 7
Charge transport in disordered graphene
E. Rostampour
Islamic Azad University, Iran
S
ince the exploration of fullerenes (C
60
), 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.
el_rostampour@yahoo.comJ Material Sci Eng 2018, Volume: 7
DOI: 10.4172/2169-0022-C3-098