Angle- and polarization-resolved luminescence from suspended and hexagonal boron nitride encapsulated MoSe2 monolayers
Journal article, 2022
The polarized photoluminescence from atomically thin transition metal dichalcogenides is a frequently applied tool to scrutinize optical selection rules and valley physics, yet it is known to sensibly depend on a variety of internal and external material and sample properties. In this work, we apply combined angle- and polarization-resolved spectroscopy to explore the interplay of excitonic physics and phenomena arising from the commonly utilized encapsulation procedure on the optical properties of atomically thinMoSe2.We probe monolayers prepared in both suspended and encapsulated manners.We show that the hBN encapsulation significantly enhances the linear polarization of exciton photoluminescence emission at large emission angles. This degree of linear polarization of excitons can increase up to ∼17% in the hBN encapsulated samples. As we confirm by finite-difference time-domain simulations, it can be directly connected to the optical anisotropy of the hBN layers. In comparison, the linear polarization at finite exciton momenta is significantly reduced in a suspendedMoSe2 monolayer, and becomes notable only in cryogenic conditions. This phenomenon strongly suggests that the effect is rooted in the k-dependent anisotropic exchange coupling inherent in2Dexcitons.Our results have strong implications on further studies on valley contrasting selection rules and valley coherence phenomena using standard suspended and encapsulated samples.
Molybdenum compounds
Anisotropy
Finite difference time domain method
Excitons
photoluminescence
Author
Bo Han
The Carl von Ossietzky University of Oldenburg
Sven Stephan
The Carl von Ossietzky University of Oldenburg
J. J.P. Thompson
Philipps University Marburg
Martin Esmann
The Carl von Ossietzky University of Oldenburg
Carlos Anton-Solanas
The Carl von Ossietzky University of Oldenburg
Hangyong Shan
The Carl von Ossietzky University of Oldenburg
Nils Kunte
The Carl von Ossietzky University of Oldenburg
Samuel Brem
Chalmers, Physics, Condensed Matter and Materials Theory
Sefaattin Tongay
Arizona State University
Christoph Lienau
The Carl von Ossietzky University of Oldenburg
Kenji Watanabe
National Institute for Materials Science (NIMS)
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Martin Silies
The Carl von Ossietzky University of Oldenburg
Ermin Malic
Philipps University Marburg
Chalmers, Physics, Condensed Matter and Materials Theory
Christian Schneider
The Carl von Ossietzky University of Oldenburg
Optica
2334-2536 (ISSN)
Vol. 9 10 1190-1196Graphene Core Project 3 (Graphene Flagship)
European Commission (EC) (EC/H2020/881603), 2020-04-01 -- 2023-03-31.
Subject Categories
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1364/OPTICA.464533