Structural and electrical changes in multilayer graphene induced by negative oxygen ion bombardment

Ion bombardment is a critical physical process that induces defects, disrupts lattice symmetry, and facilitates ion implantation in graphene, leading to significant implications for tailoring its electronic, optical and mechanical properties. This phenomenon plays an important role in understanding the nature of materials in irradiative environment. In this study, the effects of oxygen ion bombardment on graphene were investigated, resulting in a transition from a semi-metallic to a semiconducting behaviour, accompanied by the opening of a bandgap. The magnitude of this bandgap opening was found to depend on the exposure time of oxygen ion bombardment. Specifically, exposure to negative oxygen ions with an energy of 100 KeV for 120 s resulted in a bandgap opening of 0.15 eV, which was affirmed through Raman spectroscopy. The roughness of graphene layer decreases at lower fluence of O − ions bombardment and then again increases at higher fluence, have been probed through AFM in contact mode. Moreover, the current distribution mapping observed through C-AFM displays significant changes after the ion bombardment. • Synthesis of graphene using chemical vapor deposition technique. • Transfer of graphene on SiO 2 /Si substrate using wet etching transfer method. • Negative oxygen ion bombardment on the graphene layer with energy of 100 KeV. • Shifting of Fermi level by 0.15 eV due to ion bombardment. • Current mapping using C-AFM technique before and after the ion bombardment.