| Autor: |
M CS; Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium.; NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium., Pippia G; Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium.; Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Tanghe I; NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium.; Photonics Research Group, Ghent University, 9000 Ghent, Belgium., Martín-García B; CIC nanoGUNE, Tolsa Hirbidea 76, E-20018 Donostia-San Sebastian, Spain.; IKERBASQUE Basque Foundation for Science, 48009 Bilbao, Spain., Rousaki A; Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Vandenabeele P; Department of Chemistry, Ghent University, 9000 Ghent, Belgium.; Department of Archaeology, Ghent University, 9000 Ghent, Belgium., Schiettecatte P; Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Moreels I; Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium.; Department of Chemistry, Ghent University, 9000 Ghent, Belgium., Geiregat P; Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Ghent, Belgium.; NoLIMITS Center for Non-Linear Microscopy and Spectroscopy, Ghent University, 9000 Ghent, Belgium. |
| Abstrakt: |
Transition metal dichalcogenides (TMDs) are nanostructured semiconductors with prospects in optoelectronics and photocatalysis. Several bottom-up procedures to synthesize such materials have been developed yielding colloidal transition metal dichalcogenides (c-TMDs). Where such methods initially yielded multilayered sheets with indirect band gaps, recently, also the formation of monolayered c-TMDs became possible. Despite these advances, no clear picture on the charge carrier dynamics in monolayer c-TMDs exists to date. Here, we show through broadband and multiresonant pump-probe spectroscopy, that the carrier dynamics in monolayer c-TMDs are dominated by a fast electron trapping mechanism, universal to both MoS 2 and MoSe 2 , contrasting hole-dominated trapping in their multilayered counterparts. Through a detailed hyperspectral fitting procedure, sizable exciton red shifts are found and assigned to static shifts originating from both interactions with the trapped electron population and lattice heating. Our results pave the way to optimizing monolayer c-TMDs via passivation of predominantly the electron-trap sites. |
