Phase-Selective Synthesis of Rhombohedral WS2 Multilayers by Confined-Space Hybrid Metal–Organic Chemical Vapor Deposition
Rhombohedral polytype transition metal dichalcogenide (TMDC) multilayers exhibit non-centrosymmetric interlayer stacking, which yields intriguing properties such as ferroelectricity, a large second-order susceptibility coefficient χ(2), giant valley coherence, and a bulk photovoltaic effect. These p...
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Veröffentlicht in: | Nano letters 2024-10, Vol.24 (41), p.12775-12782 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Rhombohedral polytype transition metal dichalcogenide (TMDC) multilayers exhibit non-centrosymmetric interlayer stacking, which yields intriguing properties such as ferroelectricity, a large second-order susceptibility coefficient χ(2), giant valley coherence, and a bulk photovoltaic effect. These properties have spurred significant interest in developing phase-selective growth methods for multilayer rhombohedral TMDC films. Here, we report a confined-space, hybrid metal–organic chemical vapor deposition method that preferentially grows 3R-WS2 multilayer films with thickness up to 130 nm. We confirm the 3R stacking structure via polarization-resolved second-harmonic generation characterization and the 3-fold symmetry revealed by anisotropic H2O2 etching. The multilayer 3R WS2 shows a dendritic morphology, which is indicative of diffusion-limited growth. Multilayer regions with large, stepped terraces enable layer-resolved evaluation of the optical properties of 3R-WS2 via Raman, photoluminescence, and differential reflectance spectroscopy. These measurements confirm the interfacial quality and suggest ferroelectric modification of the exciton energies. |
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ISSN: | 1530-6984 1530-6992 1530-6992 |
DOI: | 10.1021/acs.nanolett.4c02766 |