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Valley dynamics probed through charged and neutral exciton emission in monolayer WSe2.
- Source :
-
Physical Review B: Condensed Matter & Materials Physics . Aug2014, Vol. 90 Issue 7, p075413-1-075413-6. 6p. - Publication Year :
- 2014
-
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. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10980121
- Volume :
- 90
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Physical Review B: Condensed Matter & Materials Physics
- Publication Type :
- Academic Journal
- Accession number :
- 98981747
- Full Text :
- https://doi.org/10.1103/PhysRevB.90.075413