Layer number determination and thickness-dependent properties of graphene grown on SiC

Wenjuan Zhu, Christos Dimitrakopoulos, Marcus Freitag, Phaedon Avouris

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Article number5738350
Pages (from-to)1196-1201
Number of pages6
JournalIEEE Transactions on Nanotechnology
Volume10
Issue number5
DOIs
StatePublished - Sep 1 2011
Externally publishedYes

Keywords

  • Electrical properties
  • graphene
  • scanning electron microscopy (SEM)
  • silicon carbide (SiC) substrate

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering

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