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HL: Fachverband Halbleiterphysik

HL 29: Poster II

HL 29.16: Poster

Dienstag, 18. März 2025, 18:00–20:00, P1

High-Pressure Optical Spectroscopy of Intralayer and Interlayer Excitons in 2H-MoS₂ Bilayers — •Vedhanth Senthiappan Vellaiappan Uthayasurian, Paul Steeger, Robert Schmidt, Steffen Michaelis de Vasconcellos, and Rudolf Bratschitsch — Institute of Physics and Center for Nanotechnology, University of Münster, 48149 Münster, Germany

Molybdenum disulfide (MoS₂) is a van der Waals material from the class of Transition Metal Dichalcogenides (TMDCs). In 2H-MoS₂ homo-bilayers, interlayer excitons, where the electron and hole are located in different layers, are observed with a large oscillator strength and distinct energy separation from intralayer excitons. We investigate these inter- and intralayer excitons in 2H-MoS₂ homo-bilayers under applied pressure using a diamond anvil cell [1]. Optical transmission spectra reveal that increasing pressure reduces the energy splitting between the A exciton and the interlayer exciton. Ab initio calculations, combined with our experimental observations, indicate that this behavior cannot be attributed to conventional hydrostatic compression. Instead, it results from the MoS₂ bilayer adhering to the diamond surface, which limits in-plane compression. Furthermore, we show that the unique real-space distributions and the associated contributions from the valence band are responsible for the differing pressure responses of the inter- and intralayer excitons in compressed MoS₂ bilayers. References : [1] P. Steeger et al, Nano Lett., 23, 8947 (2023)

Keywords: MoS2 Bilayer; High Pressure; Interlayer Excitons; Diamond Anvil Cell; Optical Absorption