  Transition metal dichalcogenide monolayers such as MoSe2,MoS2 and WSe2 are
direct bandgap semiconductors with original optoelectronic and spin-valley
properties. Here we report spectrally sharp, spatially localized emission in
monolayer MoSe2. We find this quantum dot like emission in samples exfoliated
onto gold substrates and also suspended flakes. Spatial mapping shows a
correlation between the location of emitters and the existence of wrinkles
(strained regions) in the flake. We tune the emission properties in magnetic
and electric fields applied perpendicular to the monolayer plane. We extract an
exciton g-factor of the discrete emitters close to -4, as for 2D excitons in
this material. In a charge tunable sample we record discrete jumps on the meV
scale as charges are added to the emitter when changing the applied voltage.
The control of the emission properties of these quantum dot like emitters paves
the way for further engineering of the light matter interaction in these
atomically thin materials.
