  Optoelectronic devices which allow rerouting, modulation and detection of the
optical signals would be extremely beneficial for telecommunication technology.
One of the most promising platforms for such devices are excitonic devices, as
they offer very efficient coupling to light. Of especial importance are those
based on indirect excitons, because of their long lifetime. Here we demonstrate
excitonic transistor and router based on bilayer of WSe2. Due to their strong
dipole moment, excitons in bilayer WSe2 can be controlled by transverse
electric field. At the same time, unlike indirect excitons in artificially
stacked heterostructures based on transition metal dichalcogenides - naturally
stacked bilayer offers long exciton lifetime, smaller non-radiative losses, and
are much simpler in fabrication.
