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 τ∼10−2–10−1ps and the mean free path l∼10–102nm for electron densities n=1012–1013cm−2. In particular, we find that the mean free path exhibits a finite jump at the phonon energy 200meV 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.