Journal
NANO LETTERS
Volume 16, Issue 9, Pages 5333-5339Publisher
AMER CHEMICAL SOC
DOI: 10.1021/acs.nanolett.6b01060
Keywords
-
Categories
Funding
- ERC Starting Grant PICSEN [306387]
- ERC Advanced Grant MOMB [320590]
- Nanofab facility of the Institute Neel, CNRS UGA
- Engineering and Physical Sciences Research Council [EP/M020479/1] Funding Source: researchfish
- EPSRC [EP/M020479/1] Funding Source: UKRI
- European Research Council (ERC) [320590, 306387] Funding Source: European Research Council (ERC)
Ask authors/readers for more resources
By implementing four-wave mixing (FWM) microspectroscopy, we measure coherence and population dynamics of the exciton transitions in monolayers of MoSe2. We reveal their dephasing times T2 and radiative lifetime T-1 in a subpicosecond (ps) range, approaching T-2 = 2T(1) and thus indicating radiatively limited dephasing at a temperature of 6 K. We elucidate the dephasing mechanisms by varying the temperature and by probing various locations on the flake exhibiting a different local disorder. At the nanosecond range, we observe the residual FWM produced by the incoherent excitons, which initially disperse toward the dark states but then relax back to the optically active states within the light cone. By introducing polarization-resolved excitation, we infer intervalley exciton dynamics, revealing an initial polarization degree of around 30%, constant during the initial subpicosecond decay, followed by the depolarization on a picosecond time scale. The FWM hyperspectral imaging reveals the doped and undoped areas of the sample, allowing us to investigate the neutral exciton, the charged one, or both transitions at the same time. In the latter, we observe the exciton-trion beating in the coherence evolution indicating their coherent coupling.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available