Island Sliding Barriers: A first-principles metric for determining remote epitaxy viability

Remote epitaxy, where a 2D van der Waals material (usually graphene) is inserted on top of the substrate before film epitaxy, has emerged as a promising path for growing (opto)electronics with lower defect rates and less stringent lattice matching requirements. The exact mechanism powering remote epitaxy has not been definitively shown, however, and it is not obvious when examining a new substrate-film pair whether they would be compatible with the remote epitaxy process. In this talk, we use first principles calculations to test several different mechanisms for determining whether a given substrate-film pair will successfully use remote epitaxy. We find that previously calculated metrics such as electrostatic potential do not hold sufficient explanatory power. We demonstrate that the sliding barrier of small islands on the surface when the atomic positions are allowed to optimize provides the most rigorous criteria for whether a given substrate-film pair is remote epitaxy active. This indicates that remote epitaxy is likely a phenomenon related to the kinetics and ease of island growth and migration on the graphene surface.