Dresden 2020 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 28: Poster: Thin Film Properties: Structure, Morphology and Composition

DS 28.10: Poster

Mittwoch, 18. März 2020, 15:00–18:00, P1A

Electron-beam-stimulated structure evolution of single-layer MoTe₂: From point to extended defects — •Janis Köster¹, Tibor Lehnert¹, Mahdi Ghorbani-Asl², Zhongbo Lee¹, Arkady Krasheninnikov², and Ute Kaiser¹ — ¹Electron Microscopy Group of Materials Science, University of Ulm, Ulm 89081, Germany — ²Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden 01328, Germany

The SALVE instrument is equipped with a Cc/Cs-corrector and operates between 20-80kV at atomic resolution. It enables the investigation of electron-beam-stimulated structural transformations in 2D materials on an atomic level. Here, we report the electron-beam-induced atom-by-atom evolution of single Te vacancies and Te divacancies in single-layer 2H-MoTe₂. At 40kV electron accelerating voltage, defect creation due to elastic interaction can be excluded because of the high mass of Te and Mo, and the observed defects originate from more complex interactions as a combination of inelastic and elastic events. We found different types of tetravacancies and trefoil-like defect structures as well as line defects in zigzag direction. Additionally, electron-beam-driven dynamics of defects were observed and their kinetic pathways were proven with DFT calculations. Our results may allow one-dimensional magnetic quantum systems in single-layer 2H-MoTe₂, by creating locally metallic quantum dots consisting of T’ phase.