Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 39: Poster: Metal Substrates

O 39.2: Poster

Dienstag, 19. März 2024, 18:00–20:00, Poster D

S on Ir(111): transition between two superstructures observed by LEED and Auger electron spectroscopy — •Alice Bremerich, Paulus Aleksa, Robin Ohmann, and Carsten Busse — Department Physik, Universität Siegen, Deutschland

Detailed knowledge of the adsorption of chalcogens on metal surfaces is of high interest to control the preparation of complex atomically thin materials like transition metal dichalcogenides (TMDC) or even their heterostructures. Furthermore, chalcogens are also useful intercalants, which can modify the interaction of 2D materials with their substrates.
We investigated the adsorption of elemental sulfur on pristine Ir(111), which was proven to be an excellent substrate for TMDCs on a graphene buffer layer. The resulting superstructures are determined by low energy electron diffraction (LEED), and with Auger electron spectroscopy (AES) we could quantify the S coverage Θ_S for each deposition to calibrate the sulfur source in terms of sulfur pressure and deposition time.
For S coverages Θ_S< 0.3 ML we observe the well-defined superstructure (√3×√3)R30^∘. For 0.3 ML<Θ_S<0.5 ML we found a transition between this and the c(4× 2) superstructure by the formation of domain walls. Here the LEED spots of the (√3×√3)R30^∘ structure split into three spots where the distance between them increases with increasing coverage until it forms the c(4× 2) structure for Θ_S> 0.5 ML.

Keywords: Ir(111); LEED; AES