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HL: Fachverband Halbleiterphysik
HL 29: Poster II
HL 29.7: Poster
Dienstag, 18. März 2025, 18:00–20:00, P1
Optical Properties of Janus Transition Metal Dichalcogenides — •Sai Shradha1, Julian Picker2, Nicole Engel1, Lukas Krelle1, Daria Markina1, Roberto Rosati3, Ermin Malic3, Andrey Turchanin2, and Bernhard Urbaszek1 — 1Institute for Condensed Matter Physics, TU Darmstadt, Darmstadt, Germany — 2Institute for Physical Chemistry, Friedrich Schiller University, Jena, Germany — 3Department of Physics, Philipps-Universität Marburg, Marburg, Germany
Janus transition metal dichalcogenides (JTMDs) have a crystal structure of X-M-Y where X and Y are chalcogens and M is a transition metal. Their asymmetric structure, with chalcogen atoms of different electronegativity above and below the transition metal, leads to an intrinsic out-of-plane electric dipole. This out-of-plane symmetry breaking in JTMDs causes Rashba splitting, vertical piezoelectricity and enhanced exciton-phonon coupling. Due to a reduced overlap of the electron and hole wave functions, excitons in JTMDs are predicted to have lower binding energies and longer lifetimes. This makes them promising candidates for photovoltaic devices. Via chemical vapour deposition (CVD), high-quality Janus monolayers have been synthesised [1]. This work investigates the optical properties of CVD-grown monolayer Janus MoSSe and WSSe. Photoluminescence, Raman and differential reflectivity spectroscopy performed at room temperature and 4K are used as the key techniques to identify and further analyse excitons and exciton-phonon coupling in such systems.
[1] Z. Gan et. al., Adv. Mater., 34, 2205226 (2022)
Keywords: MoSSe; Janus Transition Metal Dichalcogenides; Excitons; 2D-Materials