Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 20: 2D semiconductors and van der Waals heterostructures II (joint session HL/DS)
HL 20.2: Vortrag
Montag, 16. März 2020, 15:30–15:45, POT 81
Intralayer and interlayer exciton dynamics in WSe2/WS2 van-der-Waals heterostructure — •Manan Shah, Lorenz Maximilian Schneider, and Arash Rahimi-Iman — Department of Physics and Materials Sciences Center, Philipps-Universität, Marburg, 35032 Germany
The van-der-Waals heterostructures (vdW-HS) comprising atomically thin transition-metal dichalcogenides (TMDCs) provide an unprecedented level of freedom for bandgap engineering. However, the HSs give rise to more complex behaviour due to the change in effective dielectric screening, interlayer coupling strength, and moiré potential. The effectiveness of these parameters primarily depends upon the spacing, lattice constant mismatch, and the twist angle between the layers. The hybrid band structure of the vdW-HS system arising from the magnitude of these phenomena is not yet completely understood.
Here, we report a type-II WSe2/WS2 HS where the electrons accumulate in the WS2 monolayer (ML) and the holes accumulate in the WSe2 ML owing to charge transfer, giving rise to interlayer excitons. This tungsten-based HS is of particular interest due to the presence of energetically favourable spin-forbidden dark A-excitonic states and a strong excitonic binding energy. Our optical-spectroscopy results exhibit the intralayer excitons, intralayer phonon-assisted dark excitons, and interlayer excitons along with the emergence of new excitonic states with a large oscillator strength between the optical bandgap of the constituting MLs [M. Shah et al., Semiconductors (in press)].