When noncovalent interactions are stronger than covalent bonds: Bilayer graphene doped with second row atoms, aluminum, silicon, phosphorus and sulfur

Herein, we investigate bilayer graphene doped with second-row atoms using the LDA, M06-L, and VDW-DF functionals. For 2–3 at.% or lower Al and P dopings the structure with a short interlayer distance and without a covalent bond between the heteroatoms is more stable than that with a covalent bond and longer interlayer separation. However, for Si the linked structure is more stable. Doped bilayer-graphene is prone to the attachment of more heteroatoms, as reflected by the large adsorption energies, which decrease in the following order Al > Si > P. We show that it is feasible to tune the electronic properties, and the interlayer-interaction energy varying the type or amount of second row atoms.