Phonon softening and crystallographic orientation of strained graphene studied by Raman spectroscopy.
basic_science · Level V
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- Record sourced from PubMed, PMID 19380746.
- Also identified by DOI 10.1073/pnas.0811754106 and PMC identifier 2678610.
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Abstract
We present a systematic study of the Raman spectra of optical phonons in graphene monolayers under tunable uniaxial tensile stress. Both the G and 2D bands exhibit significant red shifts. The G band splits into 2 distinct subbands (G(+), G(-)) because of the strain-induced symmetry breaking. Raman scattering from the G(+) and G(-) bands shows a distinctive polarization dependence that reflects the angle between the axis of the stress and the underlying graphene crystal axes. Polarized Raman spectroscopy therefore constitutes a purely optical method for the determination of the crystallographic orientation of graphene.