Raman spectroscopy of graphene: doping and mapping

In this study, graphene samples prepared by mechanical exfoliation were examined by Raman spectroscopy. The Au electrical contacts, fabricated using photolithography, allowed the application of a gate voltage between graphene and the Si substrate. In the Raman spectra of the sample, we observed shifts of position, changes of intensity and the width variations of the G and 2D peaks with the change of the gate voltage. Spatial Raman mapping of the samples was performed showing variations in intensities of the Raman peaks in different flake regions.