Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 20: 2D Materials 4 (joint session HL/CPP/DS)
HL 20.5: Talk
Wednesday, September 7, 2022, 10:30–10:45, H36
Nonlinear Exciton Dynamics in Layered Heterostructures — •Vipin Krishna1, Xiao Chen2, Tarlan Hamzayev1, Silvana Botti2, and Giancarlo Soavi1 — 1Institute of Solid state Physics,Friedrich-Schiller-University,Jena — 2Institute of Theoretical Solid State Theory and Optics,Friedrich-Schiller-University,Jena
Transition-metal-dichalcogenides and related heterostructures(HS) are promising candidates for photonic and optoelectronic applications owing to strong light-matter coupling and electrically-tunable carrier dynamics.However,the presence of intense nonlinear effects such as Exciton-Exciton Annihilation(EEA)[1] limits the maximum realizable exciton-density,and is particularly efficient for interlayer-excitons(IL) due to their out-of-plane dipole nature[2].In this work,we systematically study the onset of EEA in type-II WS2/WSe2 HS by steady-state and nonlinear time-resolved PL.We infer that in HS the generation-rate is at least one order of magnitude larger for interlayer compared to intralayer-excitons for a given excitation-fluence, as expected from the ultrafast interlayer-charge-transfer and consequent IL formation.However,we do not observe stronger EEA for interlayer compared to intralayer-excitons and observe that for HS the recombination-dynamics are identical for both,suggesting that the EEA mechanism is dominated by the total excitonic-density via intra and interlayer-exciton interactions.Our work provides new insights on EEA mechanism, which is of paramount importance for optoelectronic-devices and study of excitonic-condensates with layered-materials.[1]Kuechle et.Al.J.OMX(2021),12.[2]Sigl et.Al.Phys.Rev.B 105,035417.