• 文献标题:   Non-linear Raman scattering intensities in graphene
  • 文献类型:   Article
  • 作  者:   GIEGOLD V, LANGE L, CIESIELSKI R, HARTSCHUH A
  • 作者关键词:  
  • 出版物名称:   NANOSCALE
  • ISSN:   2040-3364 EI 2040-3372
  • 通讯作者地址:   Ludwig Maximilians Univ Munchen
  • 被引频次:   1
  • DOI:   10.1039/c9nr10654e
  • 出版年:   2020

▎ 摘  要

We show that the Raman scattering signals of the two dominant Raman bands G and 2D of graphene sensitively depend on the laser intensity in opposite ways. High electronic temperatures reached for pulsed laser excitation lead to an asymmetric Fermi-Dirac distribution at the different optically resonant states contributing to Raman scattering. This results in a partial Pauli blocking of destructively interfering quantum pathways for G band scattering, which is observed as a super-linear increase of the G band intensity with laser power. The 2D band, on the other hand, exhibits sub-linear intensity scaling due to the blocking of constructively interfering contributions. The opposite intensity dependencies of the two bands are found to reduce the observed 2D/G ratio, a key quantity used for characterizing graphene samples, by more than factor two for electronic temperatures around 3000 K.