EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Two-dimensional (2D) antimony (Sb, "antimonene") recently attracted interest due to peculiar electronic properties and suitability as anode material in batteries. Sb however exhibits a large polymorphic/allotropic structural diversity, which is also influenced by the Sb's support. Thus understanding Sb heterostructure formation is key in 2D Sb integration. Particularly 2D Sb/graphene interfaces are highly important in electronics and batteries. We thus study here few-layered 2D Sb/graphene heterostructures by atomic-resolution (scanning) transmission electron microscopy. We find the co-existence of two Sb morphologies: First is a 2D morphology of layered β-Sb with β-Sb(001) || graphene(001) texture. Second are one-dimensional (1D) Sb nanowires which can be matched to β-Sb with β-Sb[2-21] ⊥ graphene(001) and are also closely related to thermodynamically non-preferred cubic Sb(001) || graphene(001). Importantly, both Sb morphologies show rotational van-der-Waals epitaxy with graphene. Both Sb morphologies are resilient against environmental bulk oxidation, although superficial surface Sb-oxide formation merits consideration, including novel epitaxial Sb2O3(111)/β-Sb(001) heterostructures. Exact Sb growth behavior depends on processing and substrate properties including, notably, the support underneath the graphene. This introduces the substrate underneath a direct 2D support as a key parameter in 2D Sb heterostructure formation. Our work provides insights into the rich phase and epitaxy landscape in 2D Sb and 2D Sb/graphene heterostructures.