▎ 摘　　要

We Investigate the dynamical properties of photoexcited carders In a single monolayer of graphene at room temperature in air using femtosecond time-resolved luminescence spectroscopy. The luminescence kinetics are observed in the near-Infrared region of 0.7-1.4 eV and analyzed based on the two-temperature model describing the cooling of thermalized carriers via the carrier-optical phonon Interaction. The observed luminescence In the range 0.7-0.9 eV is well reproduced by the model. In the range 1.0-1.4 eV, however, the luminescence, which decays in similar to 300 fs, cannot be reproduced by this model. These results indicate that the carrier system is not completely thermalized in similar to 300 fs. We also show the importance of the carrier-doping effect Induced by the substrate and surrounding environment in the carrier cooling dynamics and the predominance of optical phonons over acoustic phonons In the carrier-phonon interactions even at a temperature of similar to 400 K.