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 $\tau \sim 10^{ -2}-10^{ -1} \mathrm{ ps}$ and the mean free path $l \sim 10-10^2 \mathrm{ nm}$ for electron densities $n = 10^{ 12}-10^{ 13} \mathrm{ cm}^{ -2}$. In particular, we find that the mean free path exhibits a finite jump at the phonon energy $200 \mathrm{ meV}$ 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.
Categories: cond-mat.mes-hall