engleski

Charge carrier photogeneration in single- and few-layer MoS2

The primary photoexcitations in MoS2 are excitons with a binding energy close to 0.5 eV or even higher in single flakes. Their relaxation behavior has been described as the interplay of trapping, phonon-assisted interband transitions and radiative recombination. On the other hand, the observation of photocurrents and a photovoltaic effect suggests that photoexcitation of MoS2 also generate charge carriers. Using method of ultrafast spectroscopy we show the photogeneration of long-lived charge carriers in single- and few-layer flakes of MoS2 dispersed in an inert PMMA matrix. Charges are formed from both the A and B excitons with a time constant of approximately 1 ps during the fastest observed exciton relaxation process.

MoS2; charge transfer; photoexcitation; ultrafast spectroscopy

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