Ultraviolet Raman spectroscopy of graphene and transition-metal dichalcogenides

Riichiro Saito, Ahmad R.T. Nugraha, Eddwi H. Hasdeo, Syahril Siregar, Huaihong Guo, Teng Yang

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Here, we overview Raman spectroscopy of graphene and transition-metal dichalcogenides as a function of laser excitation energy EL, especially in the ultraviolet (UV) region. The double resonance G′ (or 2D) band of graphene is calculated for the laser energy range up to 7 eV. The intensity of the G′ band is proportional to EL-1 for EL≤5eV. We also discuss electronic Raman spectra and the asymmetric Breit-Wigner-Fano lineshape of the G band in graphene for UV light. Finally, transition-metal dichalcogenide materials show a strong optical absorption of the UV light at the M point at which we expect a two-dimensional van Hove singularity of density of states. The double-resonance Raman spectra for the UV light can be assigned to a combination or overtone phonons at the M point. Equi-energy contour of initial (blue line) and intermediate (red line) states in a double-resonance Raman process for (a) EL=3.49eV and (b) EL=6.00eV. In the case of EL=6.00eV, the blue and red lines are almost overlapped on each other. Gray-shaded areas are possible phonon wave vectors for the double-resonant Raman process that are measured from the center of the Brillouin zone.

Original languageEnglish
Pages (from-to)2363-2374
Number of pages12
JournalPhysica Status Solidi (B) Basic Research
Volume252
Issue number11
DOIs
Publication statusPublished - 2015 Nov

Keywords

  • Double-resonance Raman
  • Graphene
  • Raman spectroscopy
  • Transition-metal dichalcogenides
  • Ultraviolet spectroscopy
  • Van Hove singularity

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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