Dresden 2026 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 98: Ultrafast electron dynamics at surface and interfaces IV
O 98.9: Vortrag
Freitag, 13. März 2026, 11:45–12:00, TRE/MATH
Influence of sulphur vacancies on ultrafast charge separation in WS2-graphene heterostructures — •Johannes Gradl1, Niklas Hofmann1, Leonard Weigl1, Camilla Coletti2, Raül Perea-Causín3, Ermin Malic4, and Isabella Gierz1 — 1University of Regensburg, Regensburg, Germany — 2Istituto Italiano di Tecnologia, Pisa, Italy — 3AlbaNova University Center, Stockholm, Sweden — 4University of Marburg, Marburg, Germany
Ultrafast charge separation following photoexcitation, commonly observed in van der Waals heterostructures, is a key process for future optoelectronic devices that rely on the conversion of light into electricity. While electron and hole transfer rates are largely determined by band alignment and interlayer hybridization, recent experiments have revealed that defects critically affect the lifetime of the charge-separated state [1][2]. A microscopic understanding of defect-assisted charge transfer, however, remains elusive. We disentangle the role of sulphur vacancies on ultrafast charge separation and recombination in WS2-graphene heterostructures by (i) systematically increasing the defect density and (ii) switching the defect-assisted charge transfer channel on and off. Using time-resolved ARPES, we probe the resulting charge-transfer dynamics on ultrafast time scales directly in the band structure.
[1] Phys. Rev. Lett. 127, 276401, (2021)
[2] Sci. Adv. 7, eabd9061, (2021)
Keywords: graphene; WS2; defect; vacancy; charge separation