We developed a cluster ion beam system that produces negative cluster beams of C 1 -C 10 with ion current of 4.5 nA-50 A at extraction voltages ranging from 6 to 20 kV. The system uses the injector of a tandetron accelerator and was established by inserting an electrostatic scanner on its ion-optical line and modifying its Faraday cup into a substrate holder. Utilization of clusters enables ultrashallow ion implantation at energies as low as 600 eV/atom without deceleration. Small carbon clusters C 2 and C 4 were implanted into Ni/SiO 2 /Si substrates and following post-thermal treatment graphene was obtained. Raman spectroscopy showed characteristic 2D peaks with G-to-2D peak ratios revealing formation of 2-3 layers of graphene. The Raman data reveals clear effect of nonlinear cluster-surface interaction in ion beam synthesis of two-dimensional nanomaterials. Graphene as a promising material has attracted much attention since 2004 for academic interest and technological importance [1]. It has become a potential candidate material for fast electronic device applications, owing to its unique two-dimensional honey comb lattice structure and extraordinary physical properties. Prior to device applications, controllable process for deposition of graphene has to be established. [8,9]; however, in the reported process, carbon ions at rather high energy (30 keV and 80 keV) were used, which would yield a broad depth-profile of carbon in the matrix and inevitably generate irradiation defects.To prepare good quality two-dimensional nanomaterials like graphene or topological insulator films, it is necessary to develop low-and ultralow-energy ion beam technologies. In this work, we designed an ultralow-energy cluster ion beam system based on the cesium sputtering negative ion source of the injector of a tandetron accelerator, and extracted carbon cluster ion beams (C 1 -C 10 ). As an example, the carbon cluster beams were implanted into Ni films to form graphene layers, which proves ultrashallow implantation to be a successful process.The basic configuration of the modified injector consists mainly of a negative ion source, an electrostatic scanner and a sample carrier, as shown in Figure 1. The negative carbon cluster ion beam extracted from the ion source is analyzed by a switching magnet and scanned by an electric scanner prior to impinging on the substrate. Ni films with a thickness of 50 nm deposited on 300 nm-thick SiO 2 /Si were used as substrates for the cluster ion implantation.The ion source is a Cs sputtering type negative source

We develop a miniaturized chamber installed on a tandetron accelerator into which negative ions of small carbon clusters are transported. Negative clusters C − 1 -C − 10 are obtained with beam currents of 1-10 4 nA at energies of 10-20 keV. C − 2 beams of 0.2 µA are used to directly deposit carbon films on SiO2/Si substrates. Formation of ultrathin carbon films are demonstrated by Raman scattering, which reveals the evolution of the graphitic peak (1550 cm −2 ) with deposition time.