The effect of atomic-scale defects on graphene electronic structure

Abstract

Graphene, being one-atom thick, is extremely sensitive to the presence of adsorbed atoms and molecules and, more generally, to defects such as vacancies, holes and/or substitutional dopants. This feature, apart from being directly usable in molecular sensor devices, can also be employed to tune graphene electronic properties. Here we focus on those basic features of atomic-scale defects that can be useful for material design. Starting with isolated pz defects, we analyse the electronic structure of the defective substrate and how it determines the chemical reactivity towards adsorption (chemisorption) of atomic/molecular species. This is shown to produce non-random arrangement of adatoms on the surfaces. Then, we consider the reverse problem, that is how to use defects to engineer graphene electronic properties. In particular, we show that arranging defects to form honeycomb-shaped superlattices (what we may call “supergraphenes”) a sizeable gap opens in the band structure and new Dirac cones are created right close to the gap region. These possible structures might find important technological applications in the development of graphene-based logic transistors.