Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 66: 2D Materials IV: Interfacial Interactions (joint session O/CPP/HL)

O 66.8: Talk

Wednesday, March 18, 2020, 12:15–12:30, WIL B321

Control of interface alloying between silicene and a silver substrate — •Johannes Küchle¹, Aleksandr Baklanov¹, Felix Haag¹, David Duncan², Paul Ryan^2,3, Ari Seitsonen⁴, Willi Auwärter¹, and Francesco Allegretti¹ — ¹Physics Department E20, Technical University of Munich, Germany — ²Diamond Light Source, Didcot, UK — ³Imperial College London, UK — ⁴Département de Chimie, École Normale Supérieure, Paris, France

Silicene, the silicon analogue of graphene, is a promising material with unique structural and electronic properties, which has been the focus of intense research in the past decade. The epitaxial growth via deposition of silicon on solid substrates is an established strategy for silicene preparation, however, strong interfacial interactions may modify the functional properties of the resulting layer. On metal substrates, interfacial alloying may occur, but surprisingly, its role is often underestimated. Here, we present our recent experiments with soft X-ray photoelectron spectroscopy (SXPS) at various Si coverages, indicating that during the growth of the most commonly studied (4 × 4) superstructure of silicene on Ag(111) a Si-Ag surface alloy is formed. Our scanning tunneling microscopy studies resolve a yet unreported phase, which we relate to the Si-Ag alloy. Notably, we show that the alloy related component in SXPS can be largely suppressed by growing silicene on a GeAg₂ surface alloy on Ag(111). In this case, a number of distinct structures are observed by low-energy electron diffraction, which differ significantly from all previously reported superstructures of silicene.