Island Sliding Barriers: A First-Principles Metricfor Determining Remote Epitaxy Viability

Abstract

Abstract 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 electronics with lower defect rates and less stringent lattice matching requirements. The exact mechanism behind remote epitaxy has not been definitively shown, however, and it is not obvious when examining a substrate–film pair whether they would be compatible with the remote epitaxy process. In this paper, we use first-principles calculations to test several different mechanisms for determining whether a given substrate–film pair will successfully be grown with remote epitaxy. We find that previously calculated metrics such as electrostatic potential do not hold sufficient explanatory power. We find 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. We use this metric to explain remote epitaxy on nonpolar substrates, a case which was difficult to understand under previous theories. These results indicate that remote epitaxy is likely a phenomenon related to the kinetics and ease of island migration on the graphene surface.