Structures and electronic states of halogen-terminated graphene nano-flakes

•DFT calculations were carried out for halogen terminated graphene.•Effects of halogen on electronic states of graphene were examined.•It was found that the band gap is red-shifted by halogen.•Electronic states in edge region was discussed.

Halogen-functionalized graphenes are utilized as electronic devices and energy materials. In the present paper, the effects of halogen-termination of graphene edge on the structures and electronic states of graphene flakes have been investigated by means of density functional theory (DFT) method. It was found that the ionization potential (Ip) and electron affinity of graphene (EA) are blue-shifted by the halogen termination, while the excitation energy is red-shifted. The drastic change showed a possibility as electronic devices such as field-effect transistors. The change of electronic states caused by the halogen termination of graphene edge was discussed on the basis of the theoretical results.

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