Large Twist Angle dependent Ultrafast Transient Dynamics and Raman studies on MoSe2/WSe2 van der Waals Heterostructures
| Autor: | Arora, Vikas, Nayak, Pramoda K, Muthu, Victor S, Sood, A K |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Two-dimensional van der Waals heterostructures (HS) exhibit twist-angle ({\theta}) dependent interlayer charge transfer, driven by moir\'e potential that tunes the electronic band structure with varying {\theta}. Apart from the magic angles of {$\sim$}3$^{\circ}$ and {$\sim$}57.5$^{\circ}$ that show flat valence bands (twisted WSe2 bilayer), the commensurate angles of 21.8$^{\circ}$ and 38.2$^{\circ}$ reveal the Umklapp light coupling of interlayer excitons (twisted MoSe2 /WSe2 HS). We report a non-degenerate optical pump-optical probe spectroscopy and Raman spectroscopy of MoSe2/WSe2 HS at large twist angles. The recombination time of interlayer excitons reaches a minima near commensurate angles. Raman spectroscopy reveals an opposite shift in the A1g modes of MoSe2 and WSe2, with the maximum shift occurring in the vicinity of twist angles of 21.8$^{\circ}$ and 38.2$^{\circ}$. At these commensurate angles, maximum charge transfer increases Coulomb screening, reducing the interlayer exciton lifetime. This study emphasizes the significance of the large twist angle of HS in developing transition metal dichalcogenides-based optoelectronic devices. Comment: 20 pages, 5 figures |
| Databáze: | arXiv |
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