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Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities
Published on: July 24, 2015
Spectroscopy of covalently functionalized graphene
Sandip Niyogi1, Elena Bekyarova, Mikhail E Itkis
1Center for Nanoscale Science and Engineering, University of California, Riverside, California 92521, USA.
Nano Letters
|August 27, 2010
Summary
Chemically functionalizing graphene by forming covalent bonds introduces a band gap of approximately 0.4 eV. This chemical modification is distinct from physical defects and is detectable via Raman spectroscopy.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Graphene's unique electronic properties stem from its sp(2)-hybridized carbon lattice.
- Engineering a band gap in graphene is crucial for electronic applications.
- Previous studies showed band gap induction in carbon nanotubes via sidewall chemistry.
Purpose of the Study:
- To demonstrate the induction of a band gap in graphene using covalent bond-forming reactions.
- To characterize the electronic and vibrational changes resulting from aryl functionalization.
- To differentiate chemically induced changes from physical defects using spectroscopy.
Main Methods:
- Aryl functionalization of graphene to alter carbon hybridization from sp(2) to sp(3).
- Angle-resolved photoelectron spectroscopy (ARPES) to observe the induced band gap.
- Raman spectroscopy to analyze changes in vibrational modes (D, G, and 2D bands).
Main Results:
- Covalent functionalization successfully modified graphene's periodicity, inducing a band gap of approximately 0.4 eV.
- ARPES confirmed the presence of the band gap in aryl-functionalized graphene.
- Raman spectroscopy revealed distinct spectral changes in D, G, and 2D bands compared to physical defects, indicating successful chemical modification.
Conclusions:
- Covalent chemistry is an effective method for engineering a band gap in graphene.
- ARPES and Raman spectroscopy are suitable techniques for detecting and characterizing these chemical modifications.
- Chemically induced band gaps are distinguishable from those caused by physical defects in graphene.
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