Electron dynamics of the buffer layer and bilayer graphene on SiC

Alex J. Shearer, James E. Johns, Benjamin W. Caplins, David E. Suich, Mark C. Hersam, Charles B. Harris

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Abstract

Angle- and time-resolved two-photon photoemission (TPPE) was used to investigate electronic states in the buffer layer of 4H-SiC(0001). An image potential state (IPS) series was observed on this strongly surface-bound buffer layer, and dispersion measurements indicated free-electron-like behavior for all states in this series. These results were compared with TPPE taken on bilayer graphene, which also show the existence of a free-electron-like IPS series. Lifetimes for the n = 2, and n = 3 states were obtained from time-resolved TPPE; slightly increased lifetimes were observed in the bilayer graphene sample for the n = 2 the n = 3 states. Despite the large band gap of graphene at the center of the Brillouin zone, the lifetime results demonstrate that the graphene layers do not behave as a simple tunneling barrier, suggesting that the buffer layer and graphene overlayers play a direct role in the decay of IPS electrons.

Original languageEnglish
Article number231604
JournalApplied Physics Letters
Volume104
Issue number23
DOIs
Publication statusPublished - Jun 9 2014

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ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Shearer, A. J., Johns, J. E., Caplins, B. W., Suich, D. E., Hersam, M. C., & Harris, C. B. (2014). Electron dynamics of the buffer layer and bilayer graphene on SiC. Applied Physics Letters, 104(23), [231604]. https://doi.org/10.1063/1.4882236