▎ 摘　　要

The effect of the SiO2 substrate on a graphene film is investigated using realistic but computationally convenient energy-optimized models of the substrate supporting a layer of graphene. The electronic bands are calculated using density functional methods for several model substrates. This provides an estimate of the substrate charge effects on the behaviour of the bands near E-F, as well as the local variation of the Fermi energy of the graphene sheet. A model of a wavy graphene layer positioned on the substrate is used to help understand the nature of the minimum conductance of graphene.