Directional transport of interlayer excitons in MoSe₂-WSe₂ heterostructures

Control of interlayer excitons (IXs) in MoSe₂-WSe₂ heterostructures has recently been of significant interest, with promising applications to quantum technologies. Previous studies have shown that IXs can be localized by the moiré potential or electrostatic trapping, and that suppression of the moiré potential through an hBN separating layer allows for micron scale diffusion of IXs. It has also been shown that the spatial diffusion of excitons can be controlled using the interaction between the permanent dipole moment of the IX and patterned graphene gates to create a spatially varying electric field, but such studies have been limited to micron-scale gate structures. In this presentation, we show that exciton diffusion can be controlled on a much smaller scale using nanopatterned graphene gates. Specifically, we show that using a triangular graphene etch, we can create unidirectional diffusion of IXs, i.e., an excitonic diode, which can be used in technologies based on excitons in TMD heterostructures. Additionally, we have the potential to study exciton dynamics as a function of continuously varying in-plane potentials with the goal of realizing excitonic circuits.