Electron and optical phonon temperatures in electrically biased graphene

Stéphane Berciaud, Melinda Y. Han, Kin Fai Mak, Louis E. Brus, Philip Kim, Tony F. Heinz

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Abstract

We examine the intrinsic energy dissipation steps in electrically biased graphene channels. By combining in-situ measurements of the spontaneous optical emission with a Raman spectroscopy study of the graphene sample under conditions of current flow, we obtain independent information on the energy distribution of the electrons and phonons. The electrons and holes contributing to light emission are found to obey a thermal distribution, with temperatures in excess of 1500 K in the regime of current saturation. The zone-center optical phonons are also highly excited and are found to be in equilibrium with the electrons. For a given optical phonon temperature, the anharmonic downshift of the Raman G mode is smaller than expected under equilibrium conditions, suggesting that the electrons and high-energy optical phonons are not fully equilibrated with all of the phonon modes.

Original languageEnglish (US)
Article number227401
JournalPhysical review letters
Volume104
Issue number22
DOIs
StatePublished - Jun 3 2010

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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