Graphene Transistors

Bandgap of Graphene Nanomesh


  • Predict bandgap of GNM: comparison with experiment.


  • p/d tight-binding model (benchmarked with DFT [T. Boykin, JAP, 2012]).
  • Similar size of GNM unit-cell to the experiment [X. Liang, NanoLett, 2010].


  • Trend of experimental GNM bandgap captured.
  • Edge states observed: possible problem for transistor application.

Effects of Edge Roughness on Mobility in GNR


  • Understanding quantitative effects of edge roughness of GNRs on transport characteristics (mobility).


  • QTBM on linear potential drop at small bias.
  • Average effects of 200 statistical samples.


  • With mere ~3% of edge roughness can match the experiment (consistent with literature, Id-Vg simulation and experimental data).
  • Hydrogen passivation roughness effects negligible – due to small bandedge fluctuation.


  • Very small interface roughness can lower mobility to a significantly low level.

Associated Publication:

  • SungGeun Kim, Mathieu Luisier, Timothy Boykin, J. Geng, Jim Fonseca, Gerhard Klimeck, "Atomistic Simulation of Graphene Transistors", MSD review May 2012, Boston.[C365]

Tools Used:

Group member involved:

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