Formation of Ultrathin Diamond Films on Metal Substrates via Graphene–Metal Bonding

Diamond's exceptional properties make it a key material in various technologies, but synthesizing its low-dimensional form, diamane─a diamond film with atomic thickness─remains challenging. Diamane synthesis is complicated by the instability of ultrathin films, which tend to delaminate into multilayer graphene. However, chemically induced phase transitions, where the adsorption of specific atoms stabilizes the film, offer a potential solution. In this study, we explore the formation of diamane from bilayer graphene on metal surfaces using density functional theory calculations. We examine the nucleation and stabilization of the diamond phase on Ni, Cu, and Pt substrates. Our results reveal that nickel, with its close lattice match to diamond, provides the most favorable conditions for diamane synthesis, enabling stabilization at lower pressures. In contrast, copper and platinum exhibit higher energy barriers due to lattice mismatches. Platinum's unique role as a hydrogen source, however, also facilitates bonding between graphene layers.