Electronic structures and stabilities of bilayer graphene doped with boron and nitrogen

First-principles electronic-structure calculations have been performed to investigate energetics and electronic properties of boron (B) and nitrogen (N) defects in bilayer graphene. It is found that the formation energies for N-doped AB-stacked bilayers vary depending on dopant sites, whereas those for B-doped ones show almost site-independent behavior. From results of energy-band structure, B-doped and N-doped bilayer graphenes exhibit p-type and n-type electronic properties, respectively, with carriers on both two layers. It is also found that the boron and the nitrogen defects are observable in scanning tunneling microscopy (STM) images, while AA- and AB-stacking patterns of doped bilayer graphene exhibit similar STM images.