Exploring the regulatory effect of stacked layers on moiré excitons in twisted WSe₂/WSe₂/WSe₂ homotrilayer

Moiré superlattices in van der Waals structures have emerged as a powerful platform for studying the novel quantum properties of two-dimensional materials. The periodic moiré patterns generated by these structures lead to the formation of flat mini-bands, which alter the electronic energy bands of the material. The resulting flat electronic bands can greatly enhance strong correlative interactions between electrons, leading to the emergence of exotic quantum phenomena, including moiré phonons and moiré excitons. While extensive research has been conducted on the exotic quantum phenomena in twisted bilayers of transition metal dichalcogenides (TMDs), and the regulatory effect of stacked layers on moiré excitons remains unexplored. In this study, we report the fabrication of a twisted WSe₂/WSe₂/WSe₂ homotrilayer with two twist angles and investigate the influence of stacked layers on moiré excitons. Our experiments reveal multiple moiré exciton splitting peaks in the twisted trilayer, with moiré potential depths of 78 and 112 meV in the bilayer and trilayer homostructures, respectively. We also observed the splitting of the moiré excitons at 90 K, indicating the presence of a deeper moiré potential in the twisted trilayer. Moreover, we demonstrate that stacked layers can tune the moiré excitons by manipulating temperature, laser power, and magnetic field. Our results provide a new physical model for studying moiré superlattices and their quantum properties, which could potentially pave the way for the development of quantum optoelectronics.