Impact ionization and carrier multiplication in graphene

Luca Pirro, Anuj Girdhar, Yusuf Leblebici, Jean Pierre Leburton

Research output: Contribution to journalArticlepeer-review


We develop a model for carrier generation by impact ionization in graphene, which shows that this effect is non-negligible because of the vanishing energy gap, even for carrier transport in moderate electric fields. Our theory is applied to graphene field effect transistors for which we parameterize the carrier generation rate obtained previously with the Boltzmann formalism [A. Girdhar and J. Leburton, Appl. Phys. Lett. 99, 229903 (2011)] to include it in a self-consistent scheme and compute the transistor I-V characteristics. Our model shows that the drain current exhibits an up-kick at high drain biases, which is consistent with recent experimental data. We also show that carrier generation affects the electric field distribution along the transistor channel, which in turn reduces the carrier velocity.

Original languageEnglish (US)
Article number093707
JournalJournal of Applied Physics
Issue number9
StatePublished - Nov 1 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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