High-Bias Electronic Transport in Graphene Ribbon Devices

We present experimental studies of electronic transport in graphene under high electric fields. Graphene ribbon devices with varying widths and lengths are fabricated from mechanically exfoliated single-layer graphene sheets using electron beam lithography followed by oxygen plasma etching. Conductance measurements show a tendency of current saturation under high source-drain bias. In addition, we employ micro-Raman spectroscopy simultaneously with transport measurement on the current carrying device in vacuum. We observe an enhancement of the G-band anti-Stokes/Stokes intensity ratio, where the optical phonon temperature is estimated to be over $\sim $500K before device failure.