Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Radiatively limited dephasing and exciton dynamics in MoSe2 monolayers revealed with four-wave mixing microscopy

Jakubczyk, Tomasz, Delmonte, Valentin, Koperski, Maciej, Nogajewski, Karol, Faugeras, Clément, Langbein, Wolfgang Werner, Potemski, Marek and Kasprzak, Jacek 2016. Radiatively limited dephasing and exciton dynamics in MoSe2 monolayers revealed with four-wave mixing microscopy. Nano Letters 16 (9) , pp. 5333-5339. 10.1021/acs.nanolett.6b01060

[img]
Preview
PDF - Published Version
Download (2MB) | Preview

Abstract

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 T1 in a subpicosecond (ps) range, approaching T2 = 2T1 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.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
Additional Information: This is an open access article published under an ACS AuthorChoice License
Publisher: American Chemical Society
ISSN: 1530-6984
Date of First Compliant Deposit: 6 July 2017
Date of Acceptance: 4 August 2016
Last Modified: 16 Jul 2019 16:03
URI: http://orca.cf.ac.uk/id/eprint/101258

Citation Data

Cited 51 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics