Formation and Healing of Vacancies in Graphene Chemical Vapor Deposition (CVD) Growth

Abstract

The formation and kinetics of single and double vacancies in graphene chemical vapor deposition (CVD) growth on Cu(111), Ni(111), and Co(0001) surfaces are investigated by the first-principles calculation. It is found that the vacancies in graphene on the metal surfaces are dramatically different from those in free-standing graphene. The interaction between the vacancies and the metal surface and the involvement of a metal atom in the vacancy structure greatly reduce their formation energies and significantly change their diffusion barriers. Furthermore, the kinetic process of forming vacancies and the potential route of their healing during graphene CVD growth on Cu(111) and Ni(111) surfaces are explored. The results indicate that Cu is a better catalyst than Ni for the synthesis of high-quality graphene because the defects in graphene on Cu are formed in a lower concentration and can be more efficiently healed at the typical experimental temperature. This study leads to a deep insight into the atomic process of graphene growth, and the mechanism revealed in this study can be used for the experimental design of high-quality graphene synthesis.

Growth of epitaxial graphene: Theory and experiment

“…The formation of vacancy defects in graphene on the Cu(111), Ni (111) and Co(0001) surfaces has been studied using DFT calculations [364]. As mentioned above, for graphene grown on a surface different types of defects are possible due to the ability of the metal atoms to be incorporated into them.…”

“…73); however, structures where a metal atom passivates the four dangling bonds of the defect have also been proposed. As with SV, two possibilities have been considered [364]: either the metal atom comes from the substrate relaxing upwards (4DBs) or it is a free surface atom migrating around the surface and eventually being trapped by the defect (M@4DBs), see Fig. 74.…”

“…The diffusion of these vacancies on the surfaces was also calculated in [364] using the NEB method, the results of which are shown in Fig. 76(a-b) for the two most stable structures.…”

Energetics and kinetics of vacancies in monolayer graphene boron nitride heterostructures

“…Nonetheless, to our knowledge there has yet been any study directly computing v for 2D material systems. Often v is simply approximated using the Debye frequency or some other estimated constants [42,43]. The simple approximation however may be inaccurate as shown by Toyoura et al [41] In this regard, we performed some preliminary studies to directly evaluate v by computing the eigenfrequencies from first-principle calculations in order to enhance the accuracy in the prediction of D0, elaborated below.…”

Formation mechanism of overlapping grain boundaries in graphene chemical vapor deposition growth

“…Among these methods, graphene CVD growth on a transition metal surface stands out because of the potential for the massive production of high quality, very large area graphene at a relatively low cost, and the existence of numerous parameters which allow for the precise tuning of the number of graphene layers and/or the achievement of controllable doping. 5–7 In most CVD experiments, a graphene film is formed through the coalescence of a huge number of micro-sized domains. The coalescence of two graphene domains of different orientations will certainly lead to a grain boundary (GB) between them and therefore GBs in a graphene film are considered to be the main type of defects that greatly impede the quality of the graphene.…”