Dynamics of photogenerated charge carriers and excitons in transition metal dichalcogenides
Deepika Poonia a
a Delft University of Technology (TU Delft), The Netherlands, Van der Maasweg, 9, Delft, Netherlands
nanoGe Fall Meeting
Proceedings of nanoGe Fall Meeting19 (NGFM19)
#CharDy19. Charge Carrier Dynamics
Berlin, Germany, 2019 November 3rd - 8th
Organizers: Marcus Scheele and Maksym Yarema
Poster, Deepika Poonia, 415
Publication date: 18th July 2019

Transition metal di-chalcogenides soon after their discovery are acting as a basis to study various fundamental and novel physical properties from nanoscale to bulk limits. Here, we studied the photogeneration of free charge carriers and neutral excitons in two-dimensional transition metal di-chalcogenides, such as MoS2 and ReS2. The studies were performed using ultafast pump-probe spectroscopy with optical or terahertz conductivity detection.The samples were photoexcited by ultrashort pulses of varying incident photon energy and fluence. The presence of photogenerated  free charge carriers and excitons in these samples were observed  on timescales of femtoseconds up to nanoseconds.  The formation, relaxation and recombination dynamics of photogenerated free charge carriers and excitons were studied as a function of incident photon energy and we also monitor their quantum yield. The effects of pump fluence provide information about decay of charges and excitons via trapping due to defects and (Auger) recombination. The terahertz conductivity measurements yield the mobility of charge carriers and the polarizability of excitons.

This research received funding from the Netherlands Organisation for Scientific Research (NWO).

© Fundació Scito
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