Valley-hybridized gate-tunable 1D exciton confinement in MoSe₂

Controlling excitons at the nanoscale in semiconductor materials represents a formidable challenge in quantum photonics and optoelectronics fields. Monolayers of transition metal dichalcogenides (TMDs) offer inherent two-dimensional confinement and possess significant exciton binding energies, making them promising candidates for achieving electric-field-based confinement of excitons without dissociation. Exploiting the valley degree of freedom associated with these confined states further broadens the prospects for exciton engineering. Here, we show electric control of light polarization emitted from one-dimensional (1D) quantum-confined states in MoSe₂. Building on previous reports of tunable trapping potentials and linearly polarized emission, we extend this understanding by demonstrating how nonuniform in-plane electric fields enable in-situ control of these effects and highlight the role of gate-tunable valley hybridization in these localized states. Their polarization is entirely engineered through either the 1D confinement potential’s geometry or an out-of-plane magnetic field. Controlling non-uniform in-plane electric fields in TMDs enables control of the energy (up to five times its linewidth), polarization state (from circular to linear), and position of 1D confined excitonic states (5 nm. ^V-1 ).