In collaboration with the Federal University of São Carlos, the University of Brasília, the University of Southampton, and the University of Nottingham, we investigated the properties of charged excitons in large-area WS2, a transition metal dichalcogenide. We investigate in details the recombination dynamics of the different excitonic complexes of the system. We show that, in particular, the neutral and singly-charged (trion) exciton dynamics are influenced by charge injection from SiO2 substrates, which contribute to a redistribution of the exciton complexes along time. The Figure below shows the time evolution of the neutral (X), trions (T1 and T2), bound (XB), and localized ecitons (LS) as the pumping (laser) power conditions are modified, demonstrating irreversible processes in the exciton emission after long exposure times and pumping power. This work contributes to the understanding of the excitonic dynamics in this new class of materials, which may be important for future optoelectronic devices in graphene-like materials.
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