Regensburg 2025 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 49: 2D Materials: Electronic Structure and Exitations III (joint session O/HL/TT)
HL 49.3: Vortrag
Donnerstag, 20. März 2025, 11:00–11:15, H11
Influence of Edge Termination on the Electronic Structure of Single Layer MoS2 on Graphene/Ir(111) — •Alice Bremerich1, Marco Thaler2, Thais Chagas1, Borna Pielic1, Laerte Patera2, and Carsten Busse1 — 1Universität Siegen, Deutschland — 2Universität Innsbruck, Österreich
MoS2 is the prototypical semiconducting single-layer transition-metal dichalcogenide (TMDC). It exhibits a metallic edge state that induces partial charge accumulation at its edges, resulting in band bending effects. This 1D state acts as a barrier to electron transport across the edge and contributes significantly to quantum confinement effects in TMDC islands. In this study, we tune the edge state and the associated band bending by altering the edge termination of MoS2/gr/Ir(111) and investigate the resulting changes in the electronic structure by Scanning Tunneling Microscopy and Spectroscopy (STM and STS) at 8 K.
Quasi-freestanding MoS2 is grown on gr/Ir(111) by Molecular Beam Epitaxy (MBE). We prepare hexagonal islands that exhibit two geometrically different edge types (Mo- and S-type). We vary the chemical potential of sulfur and thereby modify the chemical environment of the boundaries. The partial charge at the perimeter depends on edge type as well as edge chemistry. In consequence, also the upward bending of both valence and conduction band shows distinct variations.
Keywords: Scanning Tunneling Spectroscopy; Transition Metal Dichalcogenide; Metallic Edge State