Temperature-activated layer-breathing vibrations in few-layer graphene

Chun Hung Lui, Zhipeng Ye, Courtney Keiser, Xun Xiao, Rui He

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

We investigated the low-frequency Raman spectra of freestanding few-layer graphene (FLG) at varying temperatures (400-900 K) controlled by laser heating. At high temperature, we observed the fundamental Raman mode for the lowest-frequency branch of rigid-plane layer-breathing mode (LBM) vibration. The mode frequency redshifts dramatically from 81 cm-1 for bilayer to 23 cm-1 for 8-layer. The thickness dependence is well described by a simple model of coupled oscillators. Notably, the LBM Raman response is unobservable at room temperature, and it is turned on at higher temperature (>600 K) with a steep increase of Raman intensity. The observation suggests that the LBM vibration is strongly suppressed by molecules adsorbed on the graphene surface but is activated as desorption occurs at high temperature.

Original languageEnglish
Pages (from-to)4615-4621
Number of pages7
JournalNano Letters
Volume14
Issue number8
DOIs
StatePublished - Aug 13 2014

Keywords

  • Raman
  • adsorption
  • few layer
  • graphene
  • layer breathing mode
  • shear mode

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