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HL: Fachverband Halbleiterphysik
HL 11: 2D Materials 2 (joint session HL/CPP/DS)
HL 11.8: Vortrag
Montag, 5. September 2022, 17:00–17:15, H36
Angle- and polarization-resolved luminescence from suspended and hBN encapsulated MoSe2 monolayers — •Bo Han1, Sven Stephan1, Joshua J.P. Thompson2, Martin Esmann1, Carlos Antón-Solanas1, Hangyong Shan1, Samuel Brem3, Christoph lienau1, Kenji Watanabe4, Takashi Taniguchi4, Martin Silies1, Ermin Malic2,3, and Christian Schneider1 — 1Carl von Ossietzky Universität, Oldenburg, Germany. — 2Philipps Universität, Marburg, Germany. — 3Chalmers University of Technology, Gothenburg, Sweden. — 4National Institute for Materials Science, Tsukuba, Japan.
We apply combined angle- and polarization-resolved spectroscopy to explore the interplay of excitonic physics and phenomena arising from the commonly utilized encapsulation on the optical properties of atomically thin transition metal dichalcogenides. In our study, we probe MoSe2 monolayers which are prepared in both a suspended and an encapsulated manner. We show that the hBN encapsulation significantly enhances the linear polarization of exciton PL at large emission angles. This degree of linear polarization of excitons can increase up to 17 % in the hBN encapsulated samples. As confirmed 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 suspended MoSe2 monolayer, and only becomes notable at cryogenic conditions. This phenomenon strongly suggest that the effect is rooted in the k-dependent anisotropic exchange coupling inherent in 2D excitons.