Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 78: 2D Materials beyond Graphene: Dynamics and Excitation

HL 78.6: Vortrag

Donnerstag, 10. März 2016, 12:00–12:15, S054

Ultrafast photocurrent dynamics in monolayer MoS2 — Eric Parzinger, Anna Vernickel, Alexander Holleitner, and •Ursula Wurstbauer — Walter Schotty Institut and Physik Department, Technical University of Munich, Germany

Atomically thin semiconducting transition metal dichalcogenides such as MoS₂ are emergent materials for optical and electronic circuits. For possible high-frequency applications, we investigate the ultrafast photocurrents in monolayer MoS₂ on a picosecond time scale utilizing a recently developed pump-probe spectroscopy [1-3]. The observed photocurrent contains three major contributions [4]. An initial ultrafast response of ≤ 5ps is followed by an exponential decay within a few hundreds of picoseconds. The third very slow contribution peaks at around 1.5 ns. This slow part dominates the overall time-integrated photocurrent intensity. We discuss the impact of laser-induced heating, the one of built-in fields at metal contacts, and the role of trap states. We acknowledge the financial support by the ERC-grant NanoREAL, the DFG excellence cluster Nanosystems Initiative Munich (NIM), and BaCaTec. [1] L. Prechtel, et al. Nature Communications 3, 646 (2012). [2] A. Brenneis, et al. Nature Nanotechnology 10, 135 (2015). [3] C. Kastl, et al. Nature Communications 6, 6617 (2015). [4] E. Parzinger et al. (2016).