Strong Quantum Confinement of 2D Excitons in an Engineered 1D Potential Induced by Proximal Ferroelectric Domain Walls.

We investigate the confinement of neutral excitons in a one-dimensional (1D) potential engineered by proximizing hexagonal boron nitride (hBN)-encapsulated monolayer MoSe to ferroelectric domain walls (DWs) in periodically poled LiNbO. Our device exploits the nanometer scale in-plane electric field gradient at the DW to induce dipolar exciton confinement via the DC Stark effect. Spatially resolved photoluminescence spectroscopy reveals the emergence of narrow emission lines redshifted from the MoSe neutral exciton by up to ∼100 meV, depending on the sample structure. The spatial distribution, excitation energy response, and polarization properties of the emission are consistent with the signatures of 1D-confined excitons. The large electric-field gradients accessible via proximal ferroelectric systems open up new avenues for the creation of robust quantum-confined excitons in atomically thin materials and their heterostructures.