Silicene, the two-dimensional (2D) allotrope of silicon, is a promising alternative to graphene in electronics. So far, the most direct synthesis strategy has been to grow it epitaxially on metal surfaces; however, the role of the strong silicon-metal interaction is generally poorly understood. In this work, we consider the (4 × 4)-silicene monolayer grown on Ag(111), probably the most illustrious representative of the 2D silicon family, and show that our experimental results refute the common interpretation of this system as a simple buckled, honeycomb monolayer. Instead, the presented analysis demonstrates the pervasive presence of a second silicon species, which we conclude to be a Si-Ag alloy stacked between silicene and the silver substrate. These findings question the current structural understanding of the silicene/Ag(111) interface and may raise expectations of analogous alloys in other 2D materials grown epitaxially on metal surfaces.

Silicene's pervasive surface alloy on Ag(111)

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.