Atomistic-Scale Simulations of the Graphene Growth on a Silicon Carbide Substrate Using Thermal Decomposition and Chemical Vapor Deposition

Molecular dynamics (MD) studies of graphene growth at the atomistic level can provide valuable insight for understanding its growth mechanism, which is helpful to optimize the growth conditions for synthesizing high-quality, large-scale graphene. In this work, we performed nanosecond timescale MD simulations to explore the graphene growth on a silicon carbide (SiC) substrate with the use of a newly developed ReaxFF reactive force field. On the basis of simulation results at various temperatures from 1000 to 3000 K, we identify the optimal temperature at which the high-quality graphene might be produced. Based on this, we further studied the graphene growth with the silicon thermal decomposition method, and we propose different growth mechanisms on the C-terminated (001̅) and Si-terminated (001) SiC surfaces. We also simulated graphene growth on the Si-facet of SiC substrate using the chemical vapor deposition (CVD) method through sequential C2H2 addition, in which the surface catalytic dehydrogenation reactions are included. Furthermore, the temperature effect on catalytic efficiency is discussed. The defect and grain boundary structures of the grown graphene with these two growing strategies are investigated as well. We also provide detailed guidelines on how our atomistic-scale results can assist experimental efforts to synthesize layer-tunable graphene with different growth methods.