Top oxide thickness dependence of remote phonon and charged impurity scattering in top-gated graphene

We have calculated the substrate-limited electron mobility in top-gated, SiO2-supported single-layer graphene from remote-phonon and charged impurity scattering rates. The mobility dependence on gate insulator thickness is explained in terms of the dielectric screening of remote phonons and charged impurities by the high-kappa/metal gate. We also find that the effects of high-kappa/metal gate screening are reduced at high carrier densities. Of the top gate dielectrics considered (h-BN, HfO2, and Al2O3), h-BN results in a better overall performance and most mobility improvement with a thinner top gate. (C) 2013 AIP Publishing LLC.