Ballistic hot electron transport in graphene

We theoretically study the inelastic scattering rate and the carrier mean free path for energetic hot electrons in graphene, including both electron-electron and electron-phonon interactions. Taking account of optical phonon emission and electron-electron scattering, we find that the inelastic scattering time tau similar to 10(-2)-10(-1) ps and the mean free path l similar to 10-10(2) nm for electron densities n=10(12)-10(13) cm(-2). In particular, we find that the mean free path exhibits a finite jump at the phonon energy 200 meV due to electron-phonon interaction. Our results are directly applicable to device structures where ballistic transport is relevant with inelastic scattering dominating over elastic scattering. (C) 2008 American Institute of Physics.