Transition metal dichalcogenides (TMDs) are a group of materials that are composed of a transition metal atom M from Group III or IV covalently connecting to two chalcogen atoms X in a hexagonal lattice. The layered structure exhibits weak interlayer van der Walls interaction, which reduces the electrostatic screening and thereby gives rise to novel many-body interactions between charge carriers 2 . At the monolayer limit, the reduced dimensionality, combined with the reduction of screening for Coulomb interactions, leads to the emergence of various robust quasiparticles even at room temperature. These includes excitons , trions and bi-exciton , several of which are unattainable in other systems . Trions, for instance, are one such charged excitons, i.e. one exciton bounded with an additional charge carrier. They arise from the interaction between excitons and residual free charge carriers in monolayer TMDs. The existence of trions allows electrically guiding and controlling charged particles more efficiently than excitons.