Dynamic Charge Transfer at the C$_{60}$/Graphene Interface

The charge transfer dynamics between C$_{60}$ molecules and graphene was studied using scanning probe microscopy, micro-Raman spectroscopy and transport measurement. Electrons inject from graphene to C$_{60}$ molecules due to the hybridization of energy band was observed. The charged C$_{60}$ molecules act as local electrical gates, which are thermally switching and induce the current or resistance fluctuations (such as 1/f noise) in graphene active channel. The thermally activated carrier trapping/detrapping process was found to be a dominant source for the 1/f noise at room temperature. As temperature decreased, Coulomb scattering from charged C$_{60}$ molecules became a primary influence on the current flow in graphene transistors.