Characterizing the Interfacial Behavior of 2D Materials: a Review

Here we review how the interactions of graphene and other 2D materials with their growth and any target substrates have been characterized. Quantifying such interactions is particularly useful for modeling the transfer of the 2D materials to other substrates. It should also help model the assembly of structures made of 2D materials. Distinction is made between direct and indirect methods of extracting the traction-separation relations, which are the continuum representation of the functional form of the interactions between the 2D material and the substrate of interest. Salient features of traction-separation relations include the energy, strength and range of the interaction being considered. Adhesion and separation energies have been the hallmark of linearly elastic fracture mechanics characterizations in the past. The additional information on the strength and range of interactions provided by the measured traction-separation relations allows closer reference to the force fields associated with them and help with the identification of mechanisms. It should also spur theoretical developments to account for some of the interesting features that are being observed.