Exciton confinement in 2D semiconductors by moiré domains in twisted ferroelectric layers

Exciton confinement in two-dimensional (2D) semiconductors offers a promising route toward quantum emitters and tunable light–matter interaction. Here, we demonstrate exciton trapping in monolayer MoSe₂ using localized in-plane electric fields generated by twisted ferroelectric hexagonal boron nitride (hBN) layers. The moiré ferroelectric domains in the twisted hBN produce strong and highly localized fields along their boundaries, acting on the exciton's static polarizability to create one-dimensional confinement potentials. In a dual-gated configuration with graphite top and back gates, we observe sharp excitonic resonances about 5 meV below the free exciton energy, with linearly and mutually orthogonally polarized doublet transitions split by ~1 meV. These features are consistent with 1D confinement of LO and TO bulk excitons, which we attribute to the in-plane fields generated by the ferroelectric domain boundaries in the twisted hBN layers. By changing the potentials of the top and bottom gates, we expect to modify the ferroelectric domain structure of the twisted hBN. In our spectroscopic studies, we observe correspondingly the systematic and reversible control over the emergence of the confined excitons.