Tunelamento ressonante de férmions massivos de Dirac em sistemas de simples e dupla barreiras em monocamada de grafeno
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Data
2015-04-29Autor
Teixeira, José Dilson da Silva
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Nowadays, several efforts have been made by research groups around the physical
properties of the graphene in view of the possible technological applications of their
unique structural and electronic properties. The graphene comes as a fort candidate to
substitute the inorganic semiconductors.
Initially in this work, we made a description of the graphene crystal structure to
elucidate its nature. The electronic properties of this material are attractive due to
several analogies between the transport phenomena and other phenomena studied by
quantum electrodynamic as, for instance, Klein tunneling.
From the point of view of the tight-binding approximation, we obtained the dispersion
relation and the structure of the energy bands of the graphene, thus outlining its electronic
spectrum. Also,we indicated some curious results that demonstrate the atypical nature
of this material.
The main objective of this study was to analyze the behavior of the charge carriers
by the transfer matrix technique to obtain the numerical solution of transmissivity,
conductance and tunneling current density in the graphene. The transmissividade was
analyzed as function of the incident energy and of the angle of incidence for systems with
single and double potential barriers, emphasizing the effect of the variation of the gap
of energy. We also verified quantum oscillations due to Fabry -Pérot interference and
Klein tunneling - an unique property in the graphene. The insertion of the energy gap
generated the gap in the transmissivity curve, as well as resonant peaks that become
more sharper with the increment of that gap.
From the transmissivity results, we enlarged our understanding of the electronic properties
in relation to conductance and current density in the graphene. Such properties
are shown quite favorable the production of nanoelectronic devices of high performance..