Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy
The ultrafast carrier dynamics of junctions between two chemically identical, but electronically distinct, transition metal dichalcogenides (TMDs) remains largely unknown. Here, we employ time-resolved photoemission electron microscopy (TR-PEEM) to probe the ultrafast carrier dynamics of a monolayer...
| Main Authors: | , , , , , , , , , , , , , |
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| Format: | Journal Article |
| Language: | English |
| Published: |
2024
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| Online Access: | https://hdl.handle.net/10356/174681 |
| _version_ | 1826128832660242432 |
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| author | Xu, Ce Barden, Natalie Alexeev, Evgeny M. Wang, Xiaoli Long, Run Cadore, Alisson R. Paradisanos, Ioannis Ott, Anna K. Soavi, Giancarlo Tongay, Sefaattin Cerullo, Giulio Ferrari, Andrea C. Prezhdo, Oleg V. Loh, Zhi-Heng |
| author2 | School of Chemistry, Chemical Engineering and Biotechnology |
| author_facet | School of Chemistry, Chemical Engineering and Biotechnology Xu, Ce Barden, Natalie Alexeev, Evgeny M. Wang, Xiaoli Long, Run Cadore, Alisson R. Paradisanos, Ioannis Ott, Anna K. Soavi, Giancarlo Tongay, Sefaattin Cerullo, Giulio Ferrari, Andrea C. Prezhdo, Oleg V. Loh, Zhi-Heng |
| author_sort | Xu, Ce |
| collection | NTU |
| description | The ultrafast carrier dynamics of junctions between two chemically identical, but electronically distinct, transition metal dichalcogenides (TMDs) remains largely unknown. Here, we employ time-resolved photoemission electron microscopy (TR-PEEM) to probe the ultrafast carrier dynamics of a monolayer-to-multilayer (1L-ML) WSe2 junction. The TR-PEEM signals recorded for the individual components of the junction reveal the sub-ps carrier cooling dynamics of 1L- and 7L-WSe2, as well as few-ps exciton-exciton annihilation occurring on 1L-WSe2. We observe ultrafast interfacial hole (h) transfer from 1L- to 7L-WSe2 on an ∼0.2 ps time scale. The resultant excess h density in 7L-WSe2 decays by carrier recombination across the junction interface on an ∼100 ps time scale. Reminiscent of the behavior at a depletion region, the TR-PEEM image reveals the h density accumulation on the 7L-WSe2 interface, with a decay length ∼0.60 ± 0.17 μm. These charge transfer and recombination dynamics are in agreement with ab initio quantum dynamics. The computed orbital densities reveal that charge transfer occurs from the basal plane, which extends over both 1L and ML regions, to the upper plane localized on the ML region. This mode of charge transfer is distinctive to chemically homogeneous junctions of layered materials and constitutes an additional carrier deactivation pathway that should be considered in studies of 1L-TMDs found alongside their ML, a common occurrence in exfoliated samples. |
| first_indexed | 2024-10-01T07:31:20Z |
| format | Journal Article |
| id | ntu-10356/174681 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T07:31:20Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | ntu-10356/1746812024-04-12T15:32:17Z Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy Xu, Ce Barden, Natalie Alexeev, Evgeny M. Wang, Xiaoli Long, Run Cadore, Alisson R. Paradisanos, Ioannis Ott, Anna K. Soavi, Giancarlo Tongay, Sefaattin Cerullo, Giulio Ferrari, Andrea C. Prezhdo, Oleg V. Loh, Zhi-Heng School of Chemistry, Chemical Engineering and Biotechnology School of Physical and Mathematical Sciences Chemistry Transition metal dichalcogenides Lateral junction The ultrafast carrier dynamics of junctions between two chemically identical, but electronically distinct, transition metal dichalcogenides (TMDs) remains largely unknown. Here, we employ time-resolved photoemission electron microscopy (TR-PEEM) to probe the ultrafast carrier dynamics of a monolayer-to-multilayer (1L-ML) WSe2 junction. The TR-PEEM signals recorded for the individual components of the junction reveal the sub-ps carrier cooling dynamics of 1L- and 7L-WSe2, as well as few-ps exciton-exciton annihilation occurring on 1L-WSe2. We observe ultrafast interfacial hole (h) transfer from 1L- to 7L-WSe2 on an ∼0.2 ps time scale. The resultant excess h density in 7L-WSe2 decays by carrier recombination across the junction interface on an ∼100 ps time scale. Reminiscent of the behavior at a depletion region, the TR-PEEM image reveals the h density accumulation on the 7L-WSe2 interface, with a decay length ∼0.60 ± 0.17 μm. These charge transfer and recombination dynamics are in agreement with ab initio quantum dynamics. The computed orbital densities reveal that charge transfer occurs from the basal plane, which extends over both 1L and ML regions, to the upper plane localized on the ML region. This mode of charge transfer is distinctive to chemically homogeneous junctions of layered materials and constitutes an additional carrier deactivation pathway that should be considered in studies of 1L-TMDs found alongside their ML, a common occurrence in exfoliated samples. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Submitted/Accepted version We acknowledge funding from the Ministry of Education, Singapore (MOE2018-T2-1-081, MOE-T2EP50221-0004 and RG1/22), the A*STAR Advanced Optics in Engineering Program (1223600008), the National Natural Science Foundation of China (21973006), the EU Graphene and Quantum Flagships, ERC grants Hetero 2D, GSYNCOR, GIPT EPSRC grants EP/L0160871/1, EP/K01711X/1, EP/K017144/1, EP/V000055/1, EP/X015742/1, EU Grants Charm, Graph-X, and the U.S. National Science Foundation (CHE-2154367). 2024-04-07T12:00:58Z 2024-04-07T12:00:58Z 2024 Journal Article Xu, C., Barden, N., Alexeev, E. M., Wang, X., Long, R., Cadore, A. R., Paradisanos, I., Ott, A. K., Soavi, G., Tongay, S., Cerullo, G., Ferrari, A. C., Prezhdo, O. V. & Loh, Z. (2024). Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy. ACS Nano, 18(3), 1931-1947. https://dx.doi.org/10.1021/acsnano.3c06473 1936-0851 https://hdl.handle.net/10356/174681 10.1021/acsnano.3c06473 38197410 2-s2.0-85182560874 3 18 1931 1947 en MOE2018-T2-1-081 RG1/22 MOE-T2EP50221-0004 1223600008 ACS Nano © 2024 American Chemical Society. All rights reserved. This article may be downloaded for personal use only. Any other use requires prior permission of the copyright holder. The Version of Record is available online at http://doi.org/10.1021/acsnano.3c06473. application/pdf |
| spellingShingle | Chemistry Transition metal dichalcogenides Lateral junction Xu, Ce Barden, Natalie Alexeev, Evgeny M. Wang, Xiaoli Long, Run Cadore, Alisson R. Paradisanos, Ioannis Ott, Anna K. Soavi, Giancarlo Tongay, Sefaattin Cerullo, Giulio Ferrari, Andrea C. Prezhdo, Oleg V. Loh, Zhi-Heng Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title | Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title_full | Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title_fullStr | Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title_full_unstemmed | Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title_short | Ultrafast charge transfer and recombination dynamics in monolayer–multilayer WSe2 junctions revealed by time-resolved photoemission electron microscopy |
| title_sort | ultrafast charge transfer and recombination dynamics in monolayer multilayer wse2 junctions revealed by time resolved photoemission electron microscopy |
| topic | Chemistry Transition metal dichalcogenides Lateral junction |
| url | https://hdl.handle.net/10356/174681 |
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