Regensburg 2022 – scientific programme

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O: Fachverband Oberflächenphysik

O 65: 2D Materials 2: Growth, Structure and Substrate Interaction

O 65.3: Talk

Thursday, September 8, 2022, 11:00–11:15, S052

On the transition from MoS₂ single-layer to bilayer growth on the Au(111) surface — •Moritz Ewert¹, Lars Buß¹, Francesca Genuzio³, Tevfik Onur Menteş³, Andrea Locatelli³, Jens Falta², and Jan Ingo Flege¹ — ¹Applied Physics and Semiconductor Spectroscopy, Brandenburg University of Technology Cottbus-Senftenberg, Germany — ²Institute of Solid State Physics, University of Bremen, Germany — ³Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, Italy

MoS₂ is well known for changing from an indirect to a direct band-gap semiconductor as a single layer. Here, for the model system MoS₂/Au(111), we present in-situ studies of the continued growth of micron-size single-layer MoS₂ islands including the first formation of bilayer patches.

We have used angle-resolved photoemission spectroscopy from micrometer sized regions to investigate the local band structure of the islands’ rims and centers, showing a prevalence for bilayer and single-layer formation at the rims and centers, respectively. The bilayer patches can clearly be identified locally on the few nanometer scale employing intensity-voltage low-energy electron microscopy as a fingerprinting method. Astonishingly, micro-spot low-energy electron diffraction hints toward the nucleation of the second layer of the MoS₂ between the single layer MoS₂ and the Au(111) substrate when the step bunches formed by the single-terrace growth mechanism become sufficiently high.