Regensburg 2022 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Poster 1

HL 25.29: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P2

Ultrafast dynamics of dark states in photocurrent of TMD heterostructures — •Denis Yagodkin, Elias Ankerhold, Abhijeet Kumar, Johanna Richter, Firas Ben Moussa, Cornelius Gahl, and Kirill Bolotin — Freie Universitat Berlin

We study the photocurrent response of TMD heterostructures MoS₂/MoSe₂ with 150 femtosecond time resolution. In order to study the dynamics of transport at the interface of the heterostructure, we tune one pulse to MoS₂ excitation resonance and the second, time-delayed pulse, to that of MoSe₂. We find stark asymmetry between negative and positive delays. We attribute this asymmetry to the formation of interlayer excitons. Using a simple model of charge carriers decaying in optically dark states we successfully describe both time-resolved reflectivity and photocurrent response of heterostructures. Extracted formation time of interlayer excitons is similar to that observed in ARPES and TR-THz at room temperature. Strong response to interlayer excitons shows the potential of our technique in detecting other dark states promising for information storing and processing.