Résumé
In this communication, we report data recorded by in situ Raman experiments on single-layer (SLG) and bilayer (BLG) graphene during exposure to rubidium vapor. By this way, we have been able to follow continuously the changes of the G and 2D bands features over a broad doping range (up to about 1014 electrons/cm2). From the comparison with theoretical predictions, we state that the evolution of the G-mode in SLG is understood as resulting of the competition between adiabatic and non-adiabatic effects in presence of a substrate pinning effect which inhibits the charge-induced lattice expansion of graphene layer [1]. For BLG, the added electrons are shown to be first confined in the top layer before a more symmetric charge repartition at high level doping. The evolution of the 2D band of BLG suggests an unexpected increase of the phonon dispersion upon doping [1]. [1] R. Parret et al. ACS Nano (2012)