Open Access Nano Express

Quantum transport simulations of graphene nanoribbon devices using Dirac equation calibrated with tight-binding π-bond model

Sai-Kong Chin1*, Kai-Tak Lam2, Dawei Seah2 and Gengchiau Liang2

Author Affiliations

1 Institute of High Performance Computing, A*STAR, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632, Singapore

2 Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576, Singapore

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Nanoscale Research Letters 2012, 7:114  doi:10.1186/1556-276X-7-114

Published: 10 February 2012

Abstract

We present an efficient approach to study the carrier transport in graphene nanoribbon (GNR) devices using the non-equilibrium Green's function approach (NEGF) based on the Dirac equation calibrated to the tight-binding π-bond model for graphene. The approach has the advantage of the computational efficiency of the Dirac equation and still captures sufficient quantitative details of the bandstructure from the tight-binding π-bond model for graphene. We demonstrate how the exact self-energies due to the leads can be calculated in the NEGF-Dirac model. We apply our approach to GNR systems of different widths subjecting to different potential profiles to characterize their device physics. Specifically, the validity and accuracy of our approach will be demonstrated by benchmarking the density of states and transmissions characteristics with that of the more expensive transport calculations for the tight-binding π-bond model.

Keywords:
graphene nanoribbons; Dirac equation; quantum transport; non-equilibrium Green's function