Strong Charge-Transfer Doping of 1 to 10 Layer Graphene by NO2
| Autor: | Amanda Ghassaei, Naeyoung Jung, Louis E. Brus, Andrew C. Crowther |
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| Rok vydání: | 2012 |
| Předmět: |
Materials science
Condensed matter physics Graphene Band gap Doping General Engineering Analytical chemistry Physics::Optics General Physics and Astronomy law.invention Delocalized electron symbols.namesake law symbols General Materials Science Physics::Chemical Physics Raman spectroscopy Bilayer graphene Absorption (electromagnetic radiation) Graphene nanoribbons |
| Zdroj: | ACS Nano. 6:1865-1875 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/nn300252a |
| Popis: | We use resonance Raman and optical reflection contrast methods to study charge transfer in 1–10 layer (1L–10L) thick graphene samples on which NO2 has adsorbed. Electrons transfer from the graphene to NO2, leaving the graphene layers doped with mobile delocalized holes. Doping follows a Langmuir-type isotherm as a function of NO2 pressure. Raman and optical contrast spectra provide independent, self-consistent measures of the hole density and distribution as a function of the number of layers (N). At high doping, as the Fermi level shift EF reaches half the laser photon energy, a resonance in the graphene G mode Raman intensity is observed. We observe a decrease of graphene optical absorption in the near-IR that is due to hole-doping. Highly doped graphene is more optically transparent and much more electrically conductive than intrinsic graphene. In thicker samples, holes are effectively confined near the surface, and in these samples, a small band gap opens near the surface. We discuss the properties an... |
| Databáze: | OpenAIRE |
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