| AVS 58th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Monday Sessions |
| Session GR+TF+ET-MoA |
| Session: | Graphene: Electronic Properties and Charge Transport |
| Presenter: | Wenjuan Zhu, IBM T.J. Watson Research Center |
| Authors: | W. Zhu, IBM T.J. Watson Research Center C. Dimitrakopoulos, IBM T.J. Watson Research Center M. Freitag, IBM T.J. Watson Research Center Ph. Avouris, IBM T.J. Watson Research Center |
| Correspondent: | Click to Email |
The electronic properties of few-layer graphene grown on the carbon-face of silicon carbide (SiC) are found to be strongly dependent on the number of layers. The carrier mobility is larger in thicker graphene because substrate-related scattering is reduced in the higher layers. The carrier density dependence of the mobility is qualitatively different in thin and thick graphene, with the transition occurring at about 2 layers. The mobility increases with carrier density in thick graphene, similar to multi-layer graphene exfoliated from natural graphite, suggesting that the individual layers are still electrically coupled. The Hall coefficient peak value is reduced in thick graphene due to the increased density of states. A reliable and rapid characterization tool for the layer number is therefore highly desirable. To date, AFM height determination and Raman scattering are typically used since the optical contrast of graphene on SiC is weak. However, both methods suffer from low throughput. We show that the scanning electron microscopy (SEM) contrast can give similar results with much higher throughput.