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HL: Fachverband Halbleiterphysik

HL 31: 2D Materials 5 (joint session HL/CPP/DS)

HL 31.3: Vortrag

Donnerstag, 8. September 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