IMPLEMENTATION OF HYBRID MOLECULAR DYNAMICS/MONTE CARLO IN NICKEL CATALYST GROWTH FOR GRAPHENE DEPOSITION MOLECULAR DYNAMICS SIMULATION

• Main Author: Syuhada, Ibnu
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/49627
• Institution: Institut Teknologi Bandung

One of the obstacles in molecular dynamics simulations of graphene growth with nickel as catalyst is a bond switching, in which the energy leap of the nickel carbide material system that occurs naturally from the local minimum to the other local minimum, and this causes a longer simulation process. The solution used in this study is to apply the molecular dynamics/Monte Carlo hybrid method by assuming all carbon atoms have dissolved into the subsurface of the catalyst and are ready for precipitation. The advantage of this hybrid method is its ability to reduce oscillations due to the numerical approach of Newton's second law equation during the simulation process. The result of the simulation is that the interaction of carbon atom cohesion is more dominant than the interaction of adesion with nickel catalyst atom. In addition, there are three information as the dominant interaction effects in the mechanism of graphene growth for high temperature catalysts, namely carbon groups as graphene precursors, nickel atoms as guides, and solid carbon groups that trigger multi-layer graphene. Graphene growth study with silver as catalyst previously conducted through the HWC VHF PECVD reactor belonging to the ITB Physics Department produces several flakes. This can be implicitly caused by the dominance of silver-carbon adesion. Based on this study, the nickel catalyst can be the solution to grow graphene with a wider surface for the next fabrication through the reactor. In this study, also developed short-range interaction potential which refers to the redefinition of the bond order to reduce oscillations due to the interatomic potential concept approach. Bond order is defined as the fraction of energy distribution that arising from the nature of the material which always tries to maintain the state of its environment where the energy distribution depends on how much attractive energy that ultimately becomes a bond. From the simulation obtained interatomic potential suits with experimental data with several parameters, namely cohesive energy, lattice and elastic constants, and phonons of graphene.