Graphene Transistors

Objective:

• Predict bandgap of GNM: comparison with experiment.

Method:

• 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].

Results:

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

Objective:

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

Method:

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

Results:

• 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.

Conclusion:

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