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Description:

Raman spectroscopy is a precious tool for the characterization of van der Waals materials, e.g. for the determination of the layer number in thin exfoliated flakes. For sensitive materials, however, this method might turn out to be dramatically invasive. In particular, the light intensity required to obtain a significant Raman signal is sufficient to immediately photo-oxidize few-layer thick metallic van der Waals materials. In this work we investigated the impact of the environment on Raman characterization of thin NbSe2 crystals. We show that in ambient conditions the flake is locally oxidized even for very low illumination intensity. On the other hand, we observe no degradation if the Raman measurements are performed either in vacuum or on fully hBN-encapsulated samples. Interestingly, we find that covering the samples only from the top is not sufficient to prevent diffusion of oxygen within the layers.

Rights:

• https://creativecommons.org/licenses/by/3.0/legalcode
  

Keyword: Raman spectroscopy, van der Waals materials, photo-oxidation

Date published: 2020-01-01

Publisher: IOP Publishing

Journal:

• 2D Materials (ISSN: 20531583) vol. 7 issue. 1 015012

Funding:

• Deutsche Forschungsgemeinschaft GRK1570

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1088/2053-1583/ab4723

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Updated at: 2025-02-26 08:30:26 +0900

Published on MDR: 2025-02-26 08:30:26 +0900