Role of surface optical phonons in the resistivity of graphene

We have experimentally investigated the effect of surface optical phonons on the resistivity of graphene in the presence of three different substrates; HfO_2, SiO₂, and h-BN. Surface optical phonon energies of HfO₂, SiO₂ and h-BN are 22, 59, and 101 meV, respectively, and we find the temperature (T) dependence of resistivity is significantly depending on the substrate materials. The resistivity shows a linear T-dependence at low T due to acoustic phonon scattering, and becomes superlinear as surface optical phonons play an important role at higher temperatures. The transition occurs below 100 K for the graphene on HfO₂ substrates whereas the linear T-dependence deviates only after 200 K for the graphene on h-BN. Our experimental data are well fitted with the model including the remote interfacial phonon scattering by the surface optical phonons of the substrates.