Beyond double-resonant Raman scattering: UV Raman spectroscopy on graphene, graphite and carbon nanotubes

Abstract

We present an analysis of deep-UV Raman measurements of graphite, graphene and carbon nanotubes. For excitation energies above the strong optical absorption peak at the $M$ point in the Brillouin zone ($\approx 4.7\text{eV}$), we partially suppress double-resonant scattering processes and observe the two-phonon density of states of carbon nanomaterials. The measured peaks are assigned to contributions from LO, TO, and LA phonon branches, supported by calculations of the phonon dispersion. Moreover, we gain access to the infrared-active $E_{1u}$ mode in graphite. By lowering the excitation energy and thus allowing double-resonant scattering processes, we demonstrate the rise of the \textit{2D} mode in graphite with ultra-short phonon wave vectors.

References in corpus (9)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• The Raman Fingerprint of Graphene
• Uniaxial Strain in Graphene by Raman Spectroscopy: G peak splitting, Gruneisen Parameters and Sample Orientation
• Theory of double-resonant Raman spectra in graphene: intensity and line shape of defect-induced and two-phonon bands
• Splitting of the Raman $2D$ band of graphene subjected to strain
• Two-dimensional analysis of the double-resonant 2D Raman mode in bilayer graphene
• Layer number determination in graphene using out-of-plane vibrations
• Temperature evolution of infrared- and Raman-active phonons in graphite
• Dominant Phonon Wavevectors and Strain-induced Splitting of the 2D Graphene Raman Mode