Adatom Diffusion beneath Graphene

Abstract

Adatom diffusion is a key concept in surface science and may lead to many important phenomena like crystal growth, surface reconstruction, and phase transition. Sometimes such diffusion is unfavorable, so it is worth studying how to effectively suppress it. Herein, using first-principles calculations, we systematically revealed the effect of graphene coverage on adatom diffusion on metal substrates based on two factors: metal–graphene separation and lattice matching. By choosing four typical metal substrates, Cu(111), Ni(111), Pt(111), and Ru(0001), which satisfy the two factors in different aspects, we found that the influence of graphene coverage has a sequence of Gr/Cu < Gr/Pt < Gr/Ni ≪ Gr/Ru. More importantly, the calculated adatom flux beneath graphene is in perfect agreement with the experimentally observed step bunching in graphene chemical vapor deposition growth. Our theoretical model not only enriches the understanding of the interface between 2D and 3D materials but also provides guidance for suppressing adatom diffusion.