Drift and funnel effects of trions in suspended MoSe2 monolayer

Exciton transport in transition metal dichalcogenides (TMDCs) has been studied for the realization of TMD-based optoelectronic devices. However, because of their charge-neutral nature, electric control of the exciton's motion is expected to be not viable. Also, the quick recombination process of electrons and holes further hinders the transport property. In the case of charged excitons (trions), the direct control of their transport using electric-fields can be employed, analogous to conventional electronic devices. In this work, we demonstrate the drift and funnel effects of free trions in a suspended MoSe2 monolayer by exerting a static electric field. To do so, we fabricated a simple electromechanical device to control the electric fields, which increases the trion density by electrical doping and pulls down the monolayer simultaneously. We confirm that under the influence of electric force, locally excited trions were dragged and consequently funneled toward the center of the strained layer. Our research provides a direct way of controlling free trion motion and opens up the possibility for the application of trion-based optoelectronic devices.