Atomistic simulations of double layer graphene structure and its reactivity

The two-dimensional transition metal dichalcogenides (TMDs), such as WSe₂, are considered for a range of optoelectronic or energy applications. However, the structural differences in the graphene templet may strongly affect the TMD growth. To explain experimentally observed stacking-dependence of WSe₂ nucleation, we performed the ReaxFF reactive molecular dynamics simulations to 1) identify the possible stacking changes in the case of the Bernal stacked as well as twisted bilayer graphene due to an in-build strain difference between the graphene layers, and 2) assess the possible changes in reactivity of the resultant stacking configurations. In the case of the Bernal stacked bilayer graphene with in-build strain difference we observed a formation of interlayer changes in stacking order (dislocations). Moreover, if this in-build strain difference is sufficiently high, we can also observed a localized buckling of graphene. This localized buckled graphene is characterized with higher reactivity, compared to any other considered stacking configuration, and might be responsible for experimentally observed higher density of WSe₂ grown in the cases of Bernal stacked bilayer, compared to the twisted one.