Effects of mass and interaction mismatches on in-plane and cross-plane thermal transport of Si-doped graphene

•Graphene in-plane phonon transport is largely suppressed by Si dopant scattering.•Graphene/SiO2 interfacial transport is enhanced by Si doping (or lower resistance).•Weakened bonding by Si and their atomic mass increase the interfacial transport.•Effects of dopant's mass and interaction mismatch on phonon transport were found.•Doping effects on phonon kinetics were quantified using molecular dynamics.