Band gap engineering of BN sheets by interlayer dihydrogen bonding and electric field control.

An unconventional bonding: The presence of interlayer B-H⋅⋅⋅H-N dihydrogen bonds in hydrogenated bilayer BN nanosheets reduces the intrinsic large band gap of the chair-type BN conformation owing to interlayer charge transfer. In contrast, the insulating properties of the thermodynamically more stable stirrup-type bilayer BN can be engineered by applying an electric field. These results illuminate a new pathway for band gap engineering of 2D BN nanomaterials.