Imaging the crystal orientation of 2D transition metal dichalcogenides using polarization-resolved second-harmonic generation
We use laser-scanning nonlinear imaging microscopy in atomically thin transition metal dichalcogenides (TMDs) to reveal information on the crystalline orientation distribution, within the 2D lattice. In particular, we perform polarization-resolved second-harmonic generation (PSHG) imaging in a stati...
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| Auteurs principaux: | , , , , , , |
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| Format: | article |
| Langue: | EN |
| Publié: |
Institue of Optics and Electronics, Chinese Academy of Sciences
2019
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| Sujets: | |
| Accès en ligne: | https://doaj.org/article/2b725358bc5d4732b2cd72bf2444e67f |
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| Résumé: | We use laser-scanning nonlinear imaging microscopy in atomically thin transition metal dichalcogenides (TMDs) to reveal information on the crystalline orientation distribution, within the 2D lattice. In particular, we perform polarization-resolved second-harmonic generation (PSHG) imaging in a stationary, raster-scanned chemical vapor deposition (CVD)-grown WS2 flake, in order to obtain with high precision a spatially resolved map of the orientation of its main crystallographic axis (armchair orientation). By fitting the experimental PSHG images of sub-micron resolution into a generalized nonlinear model, we are able to determine the armchair orientation for every pixel of the image of the 2D material, with further improved resolution. This pixel-wise mapping of the armchair orientation of 2D WS2 allows us to distinguish between different domains, reveal fine structure, and estimate the crystal orientation variability, which can be used as a unique crystal quality marker over large areas. The necessity and superiority of a polarization-resolved analysis over intensity-only measurements is experimentally demonstrated, while the advantages of PSHG over other techniques are analysed and discussed. |
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