Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 62: Posters: Surface Reactions and Dynamics, Nanostructures

O 62.10: Poster

Wednesday, April 2, 2014, 17:30–21:00, P1

Exploring hot electron dynamics in the layered semiconductor 2H-MoS₂ by time- and angle-resolved photoelectron spectroscopy — •Petra Hein, Kerstin Hanff, Gerald Rohde, Ankatrin Stange, Michael Bauer, Lutz Kipp, and Kai Rossnagel — Institute of Experimental and Applied Physics, University of Kiel, Germany

Pump-probe experiments with ultrashort pulses delivered by femtosecond laser systems provide important insights into the dynamics of condensed matter on fundamental time scales. In particular, high-harmonic extreme ultraviolet pulses can be used to investigate the temporal evolution of the electronic structure after excitation with an optical pump pulse. Previous time-resolved photoemission studies on layered transition-metal dichalcogenides (TMDCs) have focused on the dynamics of charge-density-wave and Mott insulating phases [1]. Here, we concentrate on the photo-induced electron dynamics in semiconducting TMDCs, with the indirect bandgap semiconductor 2H-MoS₂ serving as a model system. Specifically, we study the relaxation processes of the photo-excited electrons in dependence of the pump fluence, energy, and polarization. We also report the effects of alkali metal intercalation on the band structure and electron dynamics. Possible similarities of surface-intercalated 2H-MoS₂ and monolayer 2H-MoS₂ are discussed.

[1] S. Hellmann et al., Nat. Commun. 3, 1069 (2012).