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Well separated trion and neutral excitons on superacid treated MoS<inf>2</inf>monolayers

Cadiz, F and Tricard, S and Gay, M and Lagarde, D and Wang, G and Robert, C and Renucci, P and Urbaszek, B and Marie, X (2016) Well separated trion and neutral excitons on superacid treated MoS<inf>2</inf>monolayers. Applied Physics Letters, 108. p. 251106. ISSN 0003-6951

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Abstract

� 2016 Author(s). Developments in optoelectronics and spin-optronics based on transition metal dichalcogenide monolayers (MLs) need materials with efficient optical emission and well-defined transition energies. In as-exfoliated MoS2MLs, the photoluminescence (PL) spectra even at low temperature consist typically of broad, overlapping contributions from neutral, charged excitons (trions) and localized states. Here, we show that in superacid treated MoS2MLs, the PL intensity increases by up to 60 times at room temperature. The neutral and charged exciton transitions are spectrally well separated in PL and reflectivity at T = 4 K, with linewidth for the neutral exciton of 15 meV, but both transitions have similar intensities compared to the ones in as-exfoliated MLs at the same temperature. Time resolved experiments uncover picoseconds recombination dynamics analyzed separately for charged and neutral exciton emissions. Using the chiral interband selection rules, we demonstrate optically induced valley polarization for both complexes and valley coherence for only the neutral exciton.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 20:04
Last Modified: 21 Jul 2018 20:11
DOI: