SurfaceScience21 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 105: Poster Session VIII: Graphene and beyond II

O 105.6: Poster

Donnerstag, 4. März 2021, 13:30–15:30, P

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, 85748 Garching, Germany — ²Diamond Light Source, OX11 0DE Didcot, UK — ³Imperial College London, SW7 2AZ London, UK — ⁴Département de Chimie, École Normale Supérieure, 75005 Paris, France

Silicene, the silicon analogue of graphene, is a promising material with unique structural and electronic properties, which has been in the focus of intense research during the past decade. With the epitaxial fabrication via deposition of silicon on solid substrates being the best-established growth method, silicene is susceptible to strong interfacial interactions that may drastically alter its functional properties. However, these interactions are still largely unexplored. Here, we present our recent experiments with soft X-ray photoelectron spectroscopy (SXPS) at various Si coverages in combination with X-ray standing waves, indicating that during the growth of the most commonly studied (4 x 4) superstructure of silicene on Ag(111) Si-Ag surface alloying occurs. Accordingly, our scanning tunneling microscopy (STM) studies resolve a yet unreported phase, which we interpret as a Si-Ag alloy structure, extending underneath the silicene layer. Moreover, we show that growing silicene on a sacrificial Ag₂Ge surface alloy strongly suppresses the Si-Ag alloy component in SXPS, resulting in new, distinct phases, as detected by low energy electron diffraction and STM.