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HL: Fachverband Halbleiterphysik
HL 35: Optical Properties II
HL 35.6: Vortrag
Mittwoch, 11. März 2026, 17:45–18:00, POT/0251
Bandgap and exciton engineering in two-dimensional transition Mo1−xWxSe2 alloys for next-generation photonics. — •Muhammad Hussain1, Omid Ghaebi1, Mohammad Monfared2, Marco Gruenewald1, Umer Ahsan3, Fedor Lipilin3, Jan Luxa3, Zdenek Sofer3, Ulf Peschel2,4, and Giancarlo Soavi1,4 — 1Institute of Solid-State Physics, Friedrich Schiller University Jena, Germany — 2Institute of Condensed Matter Theory and Optics, Friedrich Schiller University Jena, Germany. — 3Department of Inorganic Chemistry, University of Chemistry and Technology Prague, Czech Republic — 4Abbe Center of Photonics, Friedrich Schiller University Jena, Germany
Alloys of 2D transition metal dichalcogenides (TMDs), provide a unique platform for bandgap engineering at the atomic scale. In this work, we investigate the nonlinear optical response of Mo1−xWxSe2 alloys focusing in particular on second harmonic generation (SHG) and two-photon photoluminescence (TP-PL) [1]. We find that alloyed TMDs exhibit enhanced nonlinearities compared to their pristine counterparts. By combining SHG and TP-PL and the respective optical selection rules, we are able to extract the energy difference between 1s and 2p exciton states in samples of different alloy composition. By doing this, we find that the exciton binding energy in such alloys varies with the W composition (x). This can be used as a knob to tune not only the optical bandgap, but also the exciton binding energy by changing the alloy composition.
[1] M. Hussain, et al. Adv. Opt. Mater. 13, 01000 (2025).
Keywords: TMD Alloys; Nonlinear Optics; Excitonic Resonances; Charge Distribution Asymmetry; Optical Bandgap Tuning