Infrared spectroscopy of wafer-scale graphene

Hugen Yan, Fengnian Xia, Wenjuan Zhu, Marcus Freitag, Christos Dimitrakopoulos, Ageeth A. Bol, George Tulevski, Phaedon Avouris

Research output: Contribution to journalArticlepeer-review

Abstract

We report spectroscopy results from the mid- to far-infrared on wafer-scale graphene, grown either epitaxially on silicon carbide or by chemical vapor deposition. The free carrier absorption (Drude peak) is simultaneously obtained with the universal optical conductivity (due to interband transitions) and the wavelength at which Pauli blocking occurs due to band filling. From these, the graphene layer number, doping level, sheet resistivity, carrier mobility, and scattering rate can be inferred. The mid-IR absorption of epitaxial two-layer graphene shows a less pronounced peak at 0.37 ± 0.02 eV compared to that in exfoliated bilayer graphene. In heavily chemically doped single-layer graphene, a record high transmission reduction due to free carriers approaching 40% at 250 μm (40 cm -1) is measured in this atomically thin material, supporting the great potential of graphene in far-infrared and terahertz optoelectronics.

Original languageEnglish (US)
Pages (from-to)9854-9860
Number of pages7
JournalACS Nano
Volume5
Issue number12
DOIs
StatePublished - Dec 27 2011
Externally publishedYes

Keywords

  • Drude weight
  • chemical doping
  • grapheme
  • infrared spectroscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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