Critical Research on the Analysis of Graphene Nanoribbons Passivated with Gold, Copper and Indium

Critical Research on the Analysis of Graphene Nanoribbons Passivated with Gold, Copper and Indium

This study investigates the effect of edge-passivation on graphene nanoribbons. The geometry of
graphene is simple and regular, and infinite, planar structure can easily be created either by hand or
by taking a single layer from the crystal structure of graphene. To create a device-like structure, the
infinite sheet must be cut into a suitable shape. Such a shape, at least for electronic applications, and
it is called graphene nanoribbon (GNR). A pristine graphene monolayer can be cut into elongated
strips to form 1D structure, referred to as graphene nanoribbons (GNRs) which can be either metallic
or semiconducting depending on the type and width of edges. On the base of series of simulations it
is found that elements from Ist, IIIrd and IVth group are used as passivated elements with Armchair and
Zigzag nanoribbons instead of Hydrogen. Best characteristics for zigzag nanoribbons are presented
by elements from Ist group. All experiments are made with Gold and Copper. For armchair
nanoribbons, best characteristic are shown by elements from IIIrd group. The experiment is made with
Indium. For nanoribbon with zigzag shaped edge is used DFT (Density Functional Theory) with LDA
(Local Density Approximation). The chiral index of such nanoribbon is (3, 3). For the calculations of
armchair nanoribbon is used Extended Hückel method. The chiral index of such nanoribbon is (3, 0).
In both cases the k-point are set to 1 x 1 x 100 for na, nb and nc, respectively. For nanoribbons with
zigzag shaped edges, DFT calculations show that edge-state bands at Fermi level (EF) rise to a very
large Density of States (DOS) at EF, while Density of States of the armchair nanoribbons shows an
energy gap around Fermi level. After the calculation of Band Structure and Density of States of
armchair and zigzag nanoribbons, passivated with Gold, Copper and Indium, respectively, their
transport properties are investigated. The next after Band Structure, Density of State and
Transmission Spectrum, Bloch State is calculated and plot. Bloch States can be used to investigate
the symmetry of certain bands and how this may be releated to the transport properties. Looking at
the respective Bloch function, the wave function at G and Z are real and there is a distinct difference
between valence and conduction band Bloch functions. These findings can be useful for the
prospective GNR-based devices.

Author(s) Details

Nikolay Delibozov
Technical University of Sofia, 8, Kliment Ohridski Blvd, Sofia, Bulgaria.

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