Optical versus electron diffraction imaging of Twist-angle in 2D transition metal dichalcogenide bilayers
| Autor: | Emmanuel Stratakis, George Miltos Maragkakis, Nicolas Gauquelin, Jo Verbeeck, Daen Jannis, Andrey S. Orekhov, George Kioseoglou, Sotiris Psilodimitrakopoulos, George Kourmoulakis, Leonidas Mouchliadis |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Superlattice Physics::Optics Substrate (electronics) Condensed Matter::Materials Science symbols.namesake Scanning transmission electron microscopy Microscopy General Materials Science Materials of engineering and construction. Mechanics of materials QD1-999 business.industry Physics Mechanical Engineering Resolution (electron density) Second-harmonic generation General Chemistry Condensed Matter Physics Chemistry Electron diffraction Mechanics of Materials TA401-492 symbols Optoelectronics van der Waals force business Engineering sciences. Technology |
| Zdroj: | npj 2D Materials and Applications npj 2D Materials and Applications, Vol 5, Iss 1, Pp 1-9 (2021) |
| ISSN: | 2397-7132 |
| Popis: | Atomically thin two-dimensional (2D) materials can be vertically stacked with van der Waals bonds, which enable interlayer coupling. In the particular case of transition metal dichalcogenide (TMD) bilayers, the relative direction between the two monolayers, coined as twist-angle, modifies the crystal symmetry and creates a superlattice with exciting properties. Here, we demonstrate an all-optical method for pixel-by-pixel mapping of the twist-angle with a resolution of 0.55(°), via polarization-resolved second harmonic generation (P-SHG) microscopy and we compare it with four-dimensional scanning transmission electron microscopy (4D STEM). It is found that the twist-angle imaging of WS2 bilayers, using the P-SHG technique is in excellent agreement with that obtained using electron diffraction. The main advantages of the optical approach are that the characterization is performed on the same substrate that the device is created on and that it is three orders of magnitude faster than the 4D STEM. We envisage that the optical P-SHG imaging could become the gold standard for the quality examination of TMD superlattice-based devices. |
| Databáze: | OpenAIRE |
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