▎ 摘　　要

The structures and electronic states of boron- and nitrogen-substituted graphene chips ( B-, N-, and BN-doped graphene chips) have been investigated by means of the density functional theory (DFT) method in order to shed light on the mechanism of change in the electronic properties of graphene chips caused by heteroatoms. The atomic charge of nitrogen atoms in N- graphene was a negative value, whereas that of boron atoms in B-graphene was positive. In the case of the BN-doped graphene chip, a charge polarization such as B delta+-N delta- was found. It was also found that the B-N bond pair is preferentially formed because of the large heat of formation of the B-N bond. The BN-doped graphene chips showed a large red shift of the band gap compared with that of normal graphene. The electric states of BN-graphenes were discussed on the basis of theoretical results. (c) 2011 The Japan Society of Applied Physics