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Germanene Growth on Al(111): A Case Study of Interface Effect C

Fang, Jide, Zhao, Peng, Chen, Gang
Journal of physical chemistry 2018 v.122 no.32 pp. 18669-18681
alloys, aluminum, case studies, density functional theory, energy, hydrogenation, physical chemistry, scanning tunneling microscopy, thermal stability
Using density functional theory calculations, we have studied germanene growth on Al(111) in detail. According to the polygons in GeN (N = 1–12) structures on a substrate, three structural growth modes are studied, which would lead to the growths of single-atom-thick hexagonal lattice, Kagome lattice, and buckled hexagonal superlattice germanenes. The buckled superlattices grown on pure Al(111) could reproduce the experimental scanning tunneling microscopy images, which however do not have good energetic and thermal stabilities. Detailed energy analyses suggest the possibility of forming an Al₂Ge surface alloy, on which the growths of the buckled superlattices turn to be preferable. Furthermore, such superlattice configurations become energetically and thermally stable. Their adhesive energy is ∼83 meV/Ų, which could be further decreased by hydrogenation to facilitate their separations from the Al₂Ge substrate. These studies highlight the effects of interface modification on tuning two-dimensional material growth. Also, surface alloying could be used as an effective pretreatment method to facilitate large-quantity fabrication of germanene on Al(111).