Structural properties of amorphous carbon films by molecular dynamics simulation

Structure and properties of amorphous carbon film was investigated by molecular dynamics simulation using a Tersoff potential for carbon–carbon interaction. Quantitative determination of coordination numbers, atomic density, and pair correlation function was adapted to investigate the relationship between incident energies and structural properties. The structural properties of the amorphous carbon film made by the simulations were compared with those of the films deposited by filtered vacuum arc (FVA) process. As in the experimental result, the structural properties of the modeled film have their maximum values when the incident energy of deposited atoms is between 50 and 75 eV. At the optimum kinetic energy condition, we could observe in pair correlation functions that significant amount of carbon atoms were placed at a meta-stable site of atomic distance of 2.1 Å. By melting and quenching simulation of diamond lattice, it could be shown that the population of the meta-stable site is proportional to the quenching rate. These results suggest that the hard and dense diamond-like film could be obtained when the localized thermal spike due to the collision of the high-energy carbon ion can be effectively dissipated to the lattice.