Electronic and optical properties of graphene and graphitic ZnO nanocomposite structures.

Electronic and optical properties of graphene and graphitic ZnO (G/g-ZnO) nanocomposites have been investigated with density functional theory. Graphene interacts overall weakly with g-ZnO monolayer via van der Waals interaction. There is no charge transfer between the graphene and g-ZnO monolayer, while a charge redistribution does happen within the graphene layer itself, forming well-defined electron-hole puddles. When Al or Li is doped in the g-ZnO monolayer, substantial electron (n-type) and hole (p-type) doping can be induced in graphene, leading to well-separated electron-hole pairs at their interfaces. Improved optical properties in graphene/g-ZnO nanocomposite systems are also observed, with potential photocatalytic and photovoltaic applications.