A mode space (MS) tight binding approach for the simulation of armchair graphene nanoribbon FETs is discussed. It makes use of slab-dependent modes and a novel criterion for mode selection, going beyond the one based on the lowest energy subbands. For ideal ribbons, we show that by splitting the modes into decoupled groups, the new method provides results almost identical to the real space (RS) with a speedup of more than one order of magnitude. Even in the presence of edge roughness, which tends to couple the modes, the MS approach still offers a sizable computational advantage with respect to the RS, while retaining a good accuracy.
Bibliographical noteFunding Information:
Manuscript received July 22, 2009; accepted November 23, 2009. Date of publication January 8, 2010; date of current version May 11, 2011. This work was supported by the EU FP7 IST project GRAND under contract 215752 via the IU.NET Consortium. The review of this paper was arranged by Associate Editor J.-P. Leburton.
- Graphene nanoribbon (GNR) FETs
- mode-space (MS) approach
- nonequilibrium Greens functions (NEGF)
- tight binding (TB) Hamiltonian