| 초록 |
In this work, we chose a highly fluorescent rhodamine 6G and studied the ultrafast carrier dynamics of graphene/R6G/graphene sandwich systems. A broadband two color two photon fluorescence (TCTPF) was observed from near UV to IR, allowing the study on ultrafast dynamics of the two photon excited electrons from R6G. First, the TCTPF demonstrated the charge trapping transferred from the R6G molecule is mainly involved with the defect sites of the graphene as a source for the chemically enhanced Raman scattering. Also, a typical bi-exponential decaying trend induced by electron-electron scattering (within ~1.5 ps) followed by electron-phonon scattering (1.5~10 ps) in the defect sites was clearly observed with the excitation of approximately the half of the Mott transition energy density (~0.5 mJ/cm2). The decaying dynamics in the lower wavelength region (400~450 nm) shows a faster (＜10 ps decay constant) electron-electron scattering than the higher wavelength region (600~650 nm). |
