Interband scattering-induced ambipolar transport in graphene

Abstract

An ensemble Monte Carlo study of interband scattering in graphene, including impact ionization, Auger recombination and phonon-induced generation and recombination, is presented. The model rigorously considers the collinear limit condition for many-particle interband interactions in a linear dispersion bandstructure. The results show that carrier multiplication takes place even for relatively low electric fields, with collinear impact ionization being the most significant mechanism. It is also shown that the Pauli exclusion principle and the degeneracy close to the Dirac point play a critical role in limiting carrier generation at high gate voltage and low electric field. The effect of the substrate is also determinant in restricting the generation of carriers in graphene, as well as the presence of impurities or defects. Carrier multiplication leads also to a significant increase in the lattice temperature due to an enhanced inelastic phonon interaction.