Investigating the role of graphene in the formation and stability of β-phase antimonene islands

Abstract

Two-dimensional materials have shown tremendous potential for various technological applications. Particularly, 2D antimony exhibits high applicability in electronics, sensors, and batteries. This 2D material, known as antimonene, presents two stable phases: $\alpha$ (rectangular lattice) and $\beta$ (honeycomb lattice), whose formation depends on the substrate where antimony is deposited. In this study, we investigated the growth of antimonene islands on graphene, forming an antimonene/graphene heterostructure. To demonstrate the significance of graphene in the synthesis of antimonene, we also studied antimony deposited on a bare copper foil similar to the one used for the graphene substrate. Antimony deposition exhibits the $\beta$ phase antimonene structure when deposited on top of monolayer graphene, but not when deposited on a bare copper foil, nor on top of multilayer graphene. Additionally, we investigated the stability of the heterostructure after exposure to air. Pure antimony islands are formed when evaporated in high vacuum on top of graphene and copper substrates, and antimony atoms oxidize upon exposure to air. After annealing the sample in ultra-high-vacuum at temperatures lower than 200 $°$C, more than half of pure antimony is recovered and almost all oxidized antimony is desorbed from the graphene substrate. In contrast, almost none of the oxidized antimony is desorbed from the bare copper substrate, highlighting the key role of the heterostructure on the formation and preservation of the physical and chemical properties of the deposited 2D material.