Hot electron transport in suspended multilayer graphene

We study hot electron transport in short-channel suspended multilayer graphene devices created by a distinct experimental approach. For devices with semitransparent contact barriers, a dip of differential conductance (dI/dV) has been observed at source-drain bias V(d)=0, along with anomalies at higher V(d) likely induced by optical-phonon scattering. For devices with low- contact barriers, only the dI/dV dip at V(d)=0 is observed, and we find a well-fit logarithmic dependence of dI/dV on both the bias V(d) and the temperature T. The logarithmic V(d) dependence is explained with the hot electron effect and the logarithmic T dependence could be attributed to the weak localization in two dimensions.