Shot noise suppression and hopping conduction in graphene nanoribbons

Abstract

We have investigated shot noise and conduction of graphene field-effect nanoribbon devices at low temperature. By analyzing the exponential I−V characteristics of our devices in the transport gap region, we found out that transport follows variable range hopping laws at intermediate bias voltages 1<Vbias<12 mV. In parallel, we observe a strong shot noise suppression leading to very low Fano factors. The strong suppression of shot noise is consistent with inelastic hopping, in crossover from one- to two-dimensional regime, indicating that the localization length lloc<W in our nanoribbons.