Polarization and time-resolved photoluminescence spectroscopy of excitons in MoSe2 monolayers

Abstract

We investigate valley exciton dynamics in MoSe2 monolayers in polarization- and time-resolved photoluminescence (PL) spectroscopy at 4K. Following circularly polarized laser excitation, we record a low circular polarization degree of the PL of typically $\le 5\%$. This is about 10 times lower than the polarization induced under comparable conditions in MoS2 and WSe2 monolayers. The evolution of the exciton polarization as a function of excitation laser energy and power is monitored in PL excitation (PLE) experiments. Fast PL emission times are recorded for both the neutral exciton of $\le 3$ ps and for the charged exciton (trion) of 12 ps.

4 pages, 3 figures

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• Kinetic Magnetism in Triangular Moiré Materials
• Dark excitons and the elusive valley polarization in transition metal dichalcogenides
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• Phonon-assisted inter-valley scattering determines ultrafast exciton dynamics in MoSe${}_2$ bilayers
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• Assessment of valley coherence in a high-quality monolayer molybdenum diselenide
• Heteroepitaxial growth of high optical quality, wafer-scale van der Waals heterostrucutres
• Excitonic Transport and Intervalley Scattering in Exfoliated MoSe2 Monolayer Revealed by Four-Wave-Mixing Transient Grating Spectroscopy