Linear and non-linear electrical behaviors in graphene ribbon based devices

We experimentally investigate the carrier transport in back-gated graphene ribbons. The ribbons are monolayer graphene formed by the chemical vapor deposition process and transferred on the SiO2/Si substrate. Electrical measurements show that two categories of electrical behavior are distinguished, respectively, linear and nonlinear. The in-situ Raman characterization along the ribbon area highlights interesting results for the 2D peaks shift. The Raman shift variation corresponding to the position of the 2D peaks between all measured spectra extends from 2697 cm−1 to 2700 cm−1 for devices exhibiting a linear behavior. While, for the devices exhibiting a nonlinear behavior, the variation range is more important, from 2686 cm−1 to 2704 cm−1. These results reveal that the carrier density is non-uniform and localized in term of concentration over the ribbon area, and the electrical behavior appears to be strongly related to the graphene local carrier density.