Valley dynamics probed through charged and neutral exciton emission in monolayer WSe 2 - INSA Toulouse - Institut National des Sciences Appliquées de Toulouse Access content directly
Journal Articles Physical Review B: Condensed Matter and Materials Physics (1998-2015) Year : 2014

Valley dynamics probed through charged and neutral exciton emission in monolayer WSe 2

Abstract

Optical interband transitions in monolayer transition metal dichalcogenides such as WSe2 and MoS2 are governed by chiral selection rules. This allows efficient optical initialization of an electron in a specific K valley in momentum space. Here we probe the valley dynamics in monolayer WSe2 by monitoring the emission and polarization dynamics of the well-separated neutral excitons (bound electron-hole pairs) and charged excitons (trions) in photoluminescence. The neutral exciton photoluminescence intensity decay time is about 4 ps, whereas the trion emission occurs over several tens of ps. The trion polarization dynamics shows a partial, fast initial decay within tens of ps before reaching a stable polarization of ≈20%, for which a typical valley polarization decay time of the order of 1 ns can be inferred.
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Dates and versions

hal-02052132 , version 1 (28-02-2019)

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  • HAL Id : hal-02052132 , version 1

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Gang Wang, Louis Bouet, David Lagarde, M. Vidal, Andrea Balocchi, et al.. Valley dynamics probed through charged and neutral exciton emission in monolayer WSe 2. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 90 (7). ⟨hal-02052132⟩
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