Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Poster: 2D Materials
O 29.24: Poster
Dienstag, 19. März 2024, 12:30–14:30, Poster A
Optical characterization of sulfur vacencies in TMDCs under high vacuum — •Joel Verlande, André Maas, Leon Daniel, Lars Breuer, and Marika Schleberger — Universität Duisburg- Essen, Fakultät für Physik and CENIDE, Germany
The characterization of 2D Materials under non-ambient conditions offers the potential for a deeper analysis of various defects in the crystalline structure and their effects on the optoelectronic properties. Especially the investigation under a vacuum can provide us with crucial information about the actual influence of vacancies due to often occurring defect saturation by adsorbates, such as O2 or N2. These gas molecules can act as electron donors in the 2D structure that support the creation of negatively charged trions which have a higher rate of non radiating recombination. This results in a lower photoluminescent yield which could be an unfavourable property of the material.
For this study we generated sulfur vacancies in WS2 and MoS2 CVD-grown monolayers by irradiation with low energy Ar+ ions (Ekin≤ 500 eV). Subsequently the samples were analyzed by Raman and photoluminescence spectroscopy in a vacuum cell with pressures of p < 10−4 mbar. The high vacuum leads to a dissipation of the gas molecules whereby we were able to examine the influence of the adsorbates on the weight of trionic and excitonic photoluminescent emission.
Keywords: WS2; MoS2; Defects; Raman; Photoluminescence