Tuning layer-hybridized moiré excitons by the quantum-confined Stark effect

Moiré superlattices offer an unprecedented opportunity for tailoring interactions between quantum particles 1 – 11 and their coupling to electromagnetic fields 12 – 18 . Strong superlattice potentials generate moiré minibands of excitons 16 – 18 —bound pairs of electrons and holes that reside either in a single layer (intralayer excitons) or in two separate layers (interlayer excitons). Twist-angle-controlled interlayer electronic hybridization can also mix these two types of exciton to combine their strengths 13 , 19 , 20 . Here we report the direct observation of layer-hybridized moiré excitons in angle-aligned WSe 2 /WS 2 and MoSe 2 /WS 2 superlattices by optical reflectance spectroscopy. These excitons manifest a hallmark signature of strong coupling in WSe 2 /WS 2 , that is, energy-level anticrossing and oscillator strength redistribution under a vertical electric field. They also exhibit doping-dependent renormalization and hybridization that are sensitive to the electronic correlation effects. Our findings have important implications for emerging many-body states in two-dimensional semiconductors, such as exciton condensates 21 and Bose–Hubbard models 22 , and optoelectronic applications of these materials. Optical reflectance spectroscopy provides a direct observation of layer-hybridized moiré excitons in angle-aligned transition metal dichalcogenide heterostructures.