Reactive molecular dynamics simulation of the amorphous carbon growth: Effect of the carbon triple bonds

Abstract

The growth behavior of amorphous carbon (a-C) film was studied by reactive molecular dynamics simulation using the atom-by-atom deposition approach. Various reactive force field (ReaxFF) models were compared in terms of the structural properties of the resulting a-C films. By linking the structural properties of the film with the difference in the parameter sets of the ReaxFF models, we reveal that the carbon triple bond stabilization energy in the ReaxFF model, v(trip), significantly affects the growth dynamics and structural evolution of the simulated a-C films. When the negative v(trip) value is too high, the generation of a large number of C-C dimers and triple bond-terminated chain structures induces an etching-like process. In contrast, too small negative value results in an overestimation of both the formation energy for C-C dimers and the bonding energy for terminal triple bonds. By ab initio calculation of the triple bond and comparing it with the molecular static calculation using the ReaxFF models, we tailored the v(trip), value to - 13.34 kcal/mole, and the simulated a-C film has an atomic structure comparable with the existing experimental and theoretical results.