Electronic structure of graphene-based materials and their carrier transport properties

Graphene, with the amazing physical and electronic properties, has numerous unique properties compared to the existing materials. It is a two-dimensional monolayer of carbon atoms arranged in a hexagonal lattice. Three in-plane sp²-hybridized σ-bonds and one out-of-plane dangling -bond at each carbon site empowers graphene with structural flexibility and unique electronic band structure with linear dispersion relations at the Dirac points. This chapter reviews the fundamentals of graphene-like electronic structure, density of states and conductivity, and the peculiar transport properties such as negative refraction, Klein tunneling, and quantum Hall effects (QHE). The heat conduction and grain boundary effects have also been discussed. For nanoelectronic applications, one-dimensional strips of graphene called graphene nanoribbons (GNRs) are of great interests. This chapter also reviews the electronic properties of GNRs, which greatly depend on the boundary effects and quantum confinement. They can be either semiconducting or metallic according to the chirality. By applying the external electrical and magnetic field, their properties can be tuned to exploit the spintronic and magnetoresistive effects. The thermal and thermoelectric properties of various GNR structures are also reviewed in this chapter.