Effect of Charge Puddles and Ripples on the Chemical Reactivity of Single Layer Graphene Supported by SiO2/Si Substrate

Graphene fabricated on a SiO2/Si substrate by mechanical exfoliation has two features: one is charge (electron and hole) puddles which inhomogeneously distribute on graphene flakes, and the other is ripples which exist in two-dimensional crystals. The effects of these two features on the chemical reactivity of graphene flakes toward the charge transfer chemistries with nitrobenzene diazonium tetrafluoroborate are explored by Raman spectroscopy. The results indicate that the electron puddles and more corrugated regions possess enhanced chemical reactivity. The anomalously large reactivity of single layer graphene as compared to multilayer graphene can be the combined action of these two factors.