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HL: Fachverband Halbleiterphysik

HL 29: 2D Materials III: Growth and Heterostructures (joint session O/HL)

HL 29.4: Vortrag

Dienstag, 17. März 2020, 11:15–11:30, GER 38

Where the MoS₂ bilayer grows: An in situ LEEM study — •Moritz Ewert^1,2, Lars Buß^1,2, Francesca Genuzio³, Tevfik Onur Menteş³, Andrea Locatelli³, Jens Falta², and Jan Ingo Flege^1,2 — 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 34012, Italy

Molybdenum disulfide (MoS₂) is well-known for changing from an indirect to a direct semiconductor when its thickness is reduced to a single layer, rendering a high degree of growth control a necessity for optoelectronic applications. An extensively investigated model system is MoS₂ on Au(111), which using molecular beam epitaxy typically grows as clusters. Here, we present an in-situ low-energy electron microscopy (LEEM) study of the extended growth of MoS₂ at 700^∘C and 750^∘C. These conditions lead to the formation of micron-sized single-layer MoS₂ islands. The single-domain character of these islands is demonstrated by employing dark-field imaging and micro-diffraction (LEED), which allow quantifying the relative coverage of the two mirror domains. Furthermore, selected area angle-resolved photoelectron spectroscopy of these domains directly confirms their threefold symmetric electronic bandstructure. Interestingly, under certain conditions subsequent structural characterization by I(V)-LEEM clearly identifies regions where a bilayer of MoS₂ has nucleated. Parameters influencing the bilayer growth as well as its electronic properties will be discussed.