Effect of layered-coupling in twisted WSe₂ moiré superlattices

Recently, the discovery of a variety of moiré-related properties in the twisted vertical stacking of two different monolayers has attracted considerable attention. The introduction of small twist angles in transition metal dichalcogenide (TMD) heterostructures leads to the emergence of moiré potentials, which provide a fascinating platform for the study of strong interactions of electrons. While there has been extensive research on moiré excitons in twisted bilayer superlattices, the capture and study of moiré excitons in homostructure superlattices with layer-coupling effects remain elusive. Here, we present the observation of moiré excitons in the twisted 1L-WSe₂/1L-WSe₂ and 1L-WSe₂/2L-WSe₂ homostructures with various layer-coupling interactions. The results reveal that the moiré potential increases (~ 260%) as the number of underlying layers decreases, indicating the effect of layer coupling on the modulation of the moiré potential. The effects of the temperature and laser power dependence as well as valley polarization on moiré excitons were further demonstrated, and the crucial spectral features observed were explained. Our findings pave the way for exploring quantum phenomena and related applications of quantum information.