Regensburg 2022 – scientific programme
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DS: Fachverband Dünne Schichten
DS 24: 2D Materials 9 (joint session HL/CPP/DS)
DS 24.3: Talk
Thursday, September 8, 2022, 11:45–12:00, H36
Defects in 2D WS2 monolayers — Aswin Asaithambi1, Roland Kozubek1, Francesco Reale2, Erik Pollmann1, Marcel Zöllner1, Cecilia Mattevi2, Marika Schleberger1, Axel Lorke1, and •Günther Prinz1 — 1Fakultät für Physik und CENIDE, Universität Duisburg-Essen, Germany — 2Department of Materials, Imperial College London, UK
In this presentation, we report about optical characterization and manipulation of defects in tungsten disulfide (WS2) monolayers. WS2 is one prominent member of the 2D transition metal dichalcogenides (TMDC). In these materials, defects and adsorbates can easily modify e.g., conductivity, optical properties, or even create single photon emitters. For this study we used high quality WS2 CVD-grown monolayers to purposely introduce defects via irradiating them with Xe30+ ions with different fluences [1]. Low temperature photoluminescence (PL) spectra of these irradiated WS2 monolayers show two defect related broad bands, beside the excitonic contribution. By exposing these flakes to laser light with powers up to 1.5mW, the intensity of these two PL bands can be reduced. By comparing the intensity of the excitonic contribution before and after this laser processing, we don’t observe an increase in intensity, leading us to conclude, that the defects aren’t getting healed. If the samples are heated to room temperature, the defect luminescence recovers. To interpret our observation, we suggest that the defects might be attributed to vacancy defects together with adsorbates at different defect sites.
[1] A. Asaithambi et al., Phys. Status Solidi RRL 2021, 15, 2000466