Directional exciton propagation in 2D/1D hybrid structures

Coulomb-bound electron-hole pairs, known as excitons, facilitate both energy and information transport. Controlling their motion in real space, however, remains one of the major hurdles on the path towards exciton-based integrated quantum circuitry. Among prime candidates to address this challenge are single layers of transition metal dichalcogenides that offer both highly robust and mobile excitons as well as excellent opportunities to tailor excitonic energy landscapes via proximity and substrate-induced effects. Here, we introduce a highly promising platform to realize directional propagation of excitons by employing a hybrid 2D/1D approach. We integrate a hBN-encapsulated monolayer of WSe2 together with a cylindrical GaAs nanowire to form strain-induced quasi-1D transport channels for mobile excitonic quasiparticles. Time-resolved emission microscopy reveals a striking anisotropy in the propagation of excitons both at cryogenic and room temperature. Whereas their motion is strongly suppressed across the channel, excitons are able to move very efficiently along the nanowire direction. The high contrast obtained for the exciton mobilities highlights the viability of artificially created channels for excitonic transport in 2D/1D hybrid structures.