Formation of Cl-C Chemical Bonds by High-Energy Heavy Ion Irradiation of KCl/Graphene Heterostructures

Heteroatom doping into graphene has attracted wide attention for tailoring electronic, physical, and chemical properties of graphene. In order to achieve the application of doped graphene in an effective manner, it is essential to use films with a large area and a precise number of layers. Therefore, it is necessary to develop a technique for heteroatom doping directly into CVD-grown large-area graphene. In this study, high-energy heavy ion irradiation to the heterostructure of the KCl layer and the CVD-grown single-layer graphene film allowed the formation of Cl-C chemical bonds. The spectroscopic analysis indicated that the doping of graphene by Cl atoms, at a concentration of 10.2 atom %, had occurred as a result of the irradiation of 3.0 MeV Ni⁺ ions at a fluence of up to 10¹⁵ ions·cm^-2. It is shown that Cl atoms are chemically adsorbed on graphene by the formation of C-Cl bonds with the chemical reconstruction of graphene from sp²- to sp³-hybridization.