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Modeling and simulation of the electronic properties in Graphene Nanoribbons of varying widths and lengths using Tight-Binding Hamiltonian

Goh, Edric and Chin, Huei Chaeng and Wong, Kien Liong and Indra, Izzat Safwan and Tan, Michael Loong Peng (2019) Modeling and simulation of the electronic properties in Graphene Nanoribbons of varying widths and lengths using Tight-Binding Hamiltonian. Journal of Nanoelectronics and Optoelectronics, 7 (3). pp. 207-219. ISSN 2287-237X

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Official URL: http://dx.doi.org/10.1166/jno.2018.2206

Abstract

Graphene, with impressive electronic properties, have high potential in the microelectronic field. However, graphene itself is a zero bandgap material which is not suitable for digital logic gates and its application. Thus, much focus is on graphene nanoribbons (GNRs) that are narrow strips of graphene. During GNRs fabrication process, the occurrence of defects that ultimately change electronic properties of graphene is difficult to avoid. The modelling of GNRs with defects is crucial to study the non-idealities effects. In this work, nearest-neighbor tight-binding (TB) model for GNRs is presented with three main simplifying assumptions. They are utilization of basis function, Hamiltonian operator discretization and plane wave approximation. Two major edges of GNRs, armchair-edged GNRs (AGNRs) and zigzag-edged GNRs (ZGNRs) are explored. With single vacancy (SV) defects, the components within the Hamiltonian operator are transformed due to the disappearance of tight-binding energies around the missing carbon atoms in GNRs. The size of the lattices namely width and length are varied and studied. Non-equilibrium Green"s function (NEGF) formalism is employed to obtain the electronics structure namely band structure and density of states (DOS) and all simulation is implemented in MATLAB. The band structure and DOS plot are then compared between pristine and defected GNRs under varying length and width of GNRs. It is revealed that there are clear distinctions between band structure, numerical DOS and Green"s function DOS of pristine and defective GNRs.

Item Type:Article
Uncontrolled Keywords:Electronic structure, Tight binding
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions:Electrical Engineering
ID Code:85592
Deposited By: Widya Wahid
Deposited On:30 Jun 2020 16:54
Last Modified:30 Jun 2020 16:54

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