Thermal conductivity variation of graphene with patterned double-side hydrogen doping

Abstract

Using non-equilibrium molecular dynamics simulations, we investigate the thermal conductivity variation of graphene with different hydrogen doping coverage and doping orientation. It shows that the thermal conductivity of graphene decreases with increasing hydrogen doping coverage. The decreasing rate, however, depends on the doping orientation. Based on the kinetic theory of lattice thermal transport, we study the effect of doping coverage and orientation on the phonon density of states, phonon dispersion relation, phonon relaxation time, and the specific heat. While hydrogen doping has little effect on the specific heat, it decreases the phonon group velocity and increases phonon-phonon scattering in graphene. The phonon group velocity reduction is only due to the increment of doping coverage and is independent of doping orientation. A larger angle between the doping stripe orientation and the heat flux direction leads to smaller relaxation times, i.e., stronger phonon-phonon scattering, resulting in a lower thermal conductivity.