Regensburg 2022 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 24: 2D Materials 5 (joint session HL/CPP/DS)
CPP 24.1: Vortrag
Mittwoch, 7. September 2022, 09:30–09:45, H36
Dark exciton anti-funneling in monolayer transition metal dichalcogenides — •Roberto Rosati1, Robert Schmidt2, Samuel Brem1, Raül Perea-Causín3, Iris Niehues4, Johannes Kern2, Johann Adrian Preuß2, Robert Schneider2, Steffen Michaelis de Vasconcellos2, Rudolf Bratschitsch2, and Ermin Malic1,3 — 1Philipps-Universität Marburg — 2University of Münster — 3Chalmers University of Technology — 4CIC nanoGUNE BRTA
Current nanoelectronics relies on transport. While charged carriers can be controlled by electric fields, atomically thin semiconductors are governed by excitons, which are neutral electron-hole pairs. Recently, strain engineering has been introduced to manipulate exciton diffusion [1] and propagation [2] in monolayer transition metal dichalcogenides. Strain-induced energy gradients give rise to exciton funneling up to a micrometer range. Combining spatiotemporal photoluminescence measurements with microscopic theory, here we track the way of excitons in time, space and energy. Surprisingly we find that in WS2 excitons move away from high-strain regions, contrary to what we observe in MoSe2 [2]. This anti-funneling behavior can be ascribed to dark excitons, whose strain-induced energy variations are opposite compared to bright excitons. Our findings open new possibilities to control transport in exciton-dominated materials.
[1] R. Rosati et al., 2D Mater. 8, 015030 (2021).
[2] R. Rosati, R. Schmidt et al., Nat. Commun. 12, 7221 (2021).