Auger and carrier-surface phonon interaction processes in graphene on a substrate made of polar materials

Abstract

We present a theoretical study of two specific dynamical optical properties, namely Auger and surface electron-phonon interaction processes in monolayer graphene on polar substrates such asSiO2,HfO2,SiC and hexagonal BN. Thus the eigenenergies have been derived from the tight-binding Hamiltonian in monolayer graphene. Our results indicate that both Auger and electron-surface phonon interaction processes depend on the polar substrate. Such polar substrates allow for the presence of polar optical phonons localized near the graphene-substrate interface which could be a significant scattering source for graphene carriers across the long-range Fröhlich coupling. Furthermore, the linear, gapless band structure of graphene provides ideal conditions for Auger processes which are Auger recombination (AR) and impact ionization (IMI). These processes are of fundamental interest because they strongly influence the relaxation dynamics of carriers. Likewise, we have investigated the effect of various dielectrics on both Auger and electron–surface phonon scattering rates in single layer graphene by varying the temperature, the charge carrier density and the physical separation between the interface of the dielectric substrate and graphene.