• 文献标题:   Raman spectroscopy of graphene under ultrafast laser excitation
  • 文献类型:   Article
  • 作  者:   FERRANTE C, VIRGA A, BENFATTO L, MARTINATI M, DE FAZIO D, SASSI U, FASOLATO C, OTT AK, POSTORINO P, YOON D, CERULLO G, MAURI F, FERRARI AC, SCOPIGNO T
  • 作者关键词:  
  • 出版物名称:   NATURE COMMUNICATIONS
  • ISSN:   2041-1723
  • 通讯作者地址:   Univ Roma La Sapienza
  • 被引频次:   19
  • DOI:   10.1038/s41467-017-02508-x
  • 出版年:   2018

▎ 摘  要

The equilibrium optical phonons of graphene are well characterized in terms of anharmonicity and electron-phonon interactions; however, their non-equilibrium properties in the presence of hot charge carriers are still not fully explored. Here we study the Raman spectrum of graphene under ultrafast laser excitation with 3 ps pulses, which trade off between impulsive stimulation and spectral resolution. We localize energy into hot carriers, generating nonequilibrium temperatures in the similar to 1700-3100 K range, far exceeding that of the phonon bath, while simultaneously detecting the Raman response. The linewidths of both G and 2D peaks show an increase as function of the electronic temperature. We explain this as a result of the Dirac cones' broadening and electron-phonon scattering in the highly excited transient regime, important for the emerging field of graphene-based photonics and optoelectronics.