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

Abstract

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 Siterminated (001) SiC surfaces. We also simulated graphene growth on the Si-facet of SiC substrate using the chemical vapor deposition (CVD) method through sequential C 2 H 2 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.

New Insight into the Metal-Catalyst-Free Direct Chemical Vapor Deposition Growth of Graphene on Silicon Substrates

“…This suggests that the presence of SiC buffer layer facilitates the formation of relatively longer chains of carbon atoms. However, at low temperatures ( T < 2000 K), the carbon atoms diffuse very slowly on the SiCBSi surface due to the relatively strong interaction between a carbon atom and the SiCBSi surface, which yields only a few small-sized graphene-like structures . This is in agreement with our experimental CVD growth results for graphene that are discussed later (Figure a–f).…”

“…This is in agreement with our experimental CVD growth results for graphene that are discussed later (Figure a–f). However, large-area and high-quality graphene films can be obtained at temperatures >2400 K on SiC substrates rather than on a self-limited thin SiC buffer layer on Si(100) substrates (our case) …”

“…It is well known that growth temperature plays an important role in graphene formation irrespective of the substrate. , Therefore, AIMD simulations were performed to investigate the competition between graphene formation (C–C bond formation) and Si–C bond formation on the Si(100) surface, as shown in Figure , whereas only graphene formation (C–C bond formation) was investigated on the SiCBSi surface, as shown in Figure . We introduced 12 carbon atoms on the Si(100) slab and executed MD simulation at four different temperatures such as 973, 1073, 1300, and 1400 K for 5 ps.…”

Chemical vapor deposition of 2D materials: A review of modeling, simulation, and machine learning studies

“…Recently, Zhang and Duin investigated the CVD growth of graphene on silicon carbide using classical reactive MD simulations. This work involved the development of a silicon/hydrogen/graphene force field, using which the operating temperatures were found to be optimal between 1000 and 3000 K ( Zhang and Duin, 2020 ). Future work can explore the use of ReaxFF models to understand the controlled growth of graphene on various substrates.…”

“…(2012) , Elliott et al. (2013) , Zhang and Duin (2020) Wu et al. (2012) , Jiang and Hou (2015) , Göltl et al.…”