SKM 2021 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 5: 2D semiconductors and van der Waals heterostructures I (joint session HL/DS)

HL 5.1: Invited Talk

Monday, September 27, 2021, 13:30–14:00, H4

The role of chalcogen vacancies for atomic defect emission in MoS₂ — Elmar Mitterreiter¹, Bruno Schuler², Daniel Hernangómez-Pérez³, Julian Klein⁴, Jonathan Finley¹, Sivan Refaely-Abramson³, Alexander Holleitner¹, Alexander Weber-Bargioni⁵, and •Christoph Kastl¹ — ¹Walter Schottky Institute, TU Munich — ²nanotech@surfaces Laboratory, Empa — ³Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science — ⁴Massachusetts Institute of Technology — ⁵Molecular Foundry, Lawrence Berkeley National Laboratory

The microscopic understanding of defect-related modifications in 2D materials requires correlation between atomic structure and resulting macroscopic electronic, optical or excitonic properties. Combing controlled defect engineering with optical spectroscopy as well as atomic imaging and ab-initio theory, we identify the optical signature of pristine chalcogen vacancies in single layer MoS₂. [1] Vacancies introduce a narrow optical emission, markedly different from previously observed broad luminescence bands. Comparing annealed vs. He-ion treated MoS₂, we establish that the recently discovered single-photon emitters in He-ion irradiated MoS₂ originate from chalcogen vacancies. Using focused ion beam irradiation, the latter can be created site-selectively [2] with a spatial precision better than 10 nm [3], which is important for a prospective integration of defect-based single photon emitters into quantum photonic circuits. [1] E. Mitterreiter et al., Nat. Commun. 12, 3822 (2021). [2] J. Klein et al. ACS Photonics 8, 669-677 (2021). [3] E. Mitterreiter et al., Nano Lett. 20, 4437 (2020).