Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 12: 2D Materials I: Electronic Structure (joint session O/TT)
O 12.5: Vortrag
Montag, 18. März 2024, 16:00–16:15, MA 005
Tuning Intrinsic Transition Probabilities in CVD-Grown WS2 through Introduction of Sulfur Vacancies — •Leon Daniel, Charleen Lintz, Osamah Kharsah, Andre Maas, Stephan Sleziona, and Marika Schleberger — Universität Duisburg-Essen
Monolayer transition metal dichalcogenides (TMDCs) like tungsten disulfide (WS2) are highly interesting materials for optoelectronic and valleytronic applications. Although WS2 has a significantly higher quantum efficiency compared to its MoS2 counterparts, its intrinsic properties are much less studied. This study investigates the controlled creation of sulfur vacancies in chemical vapor deposition (CVD)-grown WS2 by high-temperature annealing in vacuum conditions up to 627 K. Employing in-situ photoluminescence (PL) spectroscopy, we observe a selective reduction in the intensity of the A exciton, while the B exciton remains unaffected upon introduction of vacancies. This distinctive behavior provides valuable insights into intrinsic transition probabilities associated with deliberately induced defect levels in WS2. Additionally, an increased trion emission was detected, indicating increased doping by selectively removing sulfur. Intriguingly, despite the vacancy introduction, no observable localized states are detected. Similar results are achieved through 100 eV argon ion irradiation, if the sample is annealed with high laser powers before PL measurements are conducted; we therefore attribute this to the desorption of adsorbates. Our findings suggest that low energy ion bombardment is a suitable option for selectively tailoring the material’s optical properties.