TY - JOUR
T1 - Layer number determination and thickness-dependent properties of graphene grown on SiC
AU - Zhu, Wenjuan
AU - Dimitrakopoulos, Christos
AU - Freitag, Marcus
AU - Avouris, Phaedon
N1 - Manuscript received September 23, 2010; revised January 17, 2011; accepted February 28, 2011. Date of publication March 24, 2011; date of current version September 8, 2011. This work was supported by the Defense Advanced Research Projects Agency under Contract FA8650-08-C-7838 through the Carbon Electronics for RF Applications program. The review of this paper was arranged by Associate Editor C. Zhou.
PY - 2011/9
Y1 - 2011/9
N2 - 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 multilayer graphene exfoliated from natural graphite, suggesting that the individual layers are still electrically coupled in spite of reports recording non-Bernal stacking order in C-face grown graphene. 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, atomic force microscopy 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.
AB - 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 multilayer graphene exfoliated from natural graphite, suggesting that the individual layers are still electrically coupled in spite of reports recording non-Bernal stacking order in C-face grown graphene. 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, atomic force microscopy 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.
KW - Electrical properties
KW - graphene
KW - scanning electron microscopy (SEM)
KW - silicon carbide (SiC) substrate
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U2 - 10.1109/TNANO.2011.2130536
DO - 10.1109/TNANO.2011.2130536
M3 - Article
AN - SCOPUS:80052614060
SN - 1536-125X
VL - 10
SP - 1196
EP - 1201
JO - IEEE Transactions on Nanotechnology
JF - IEEE Transactions on Nanotechnology
IS - 5
M1 - 5738350
ER -