Stacking order dependence of interlayer excitons in MoSe2/WSe2 heterobilayers

Two-dimensional transition metal dichalcogenide heterostructures provide a unique opportunity for quantum engineering of electronic and excitonic states at the nanoscale. Critical optical properties of interlayer excitons, including transition energy, optical selectivity, and quantum yield, are strongly correlated to the stacking orders. However, these optical properties could vary from sample to sample, setting an obstacle to extracting the intrinsic stacking order dependence experimentally. We report an effective method to fabricate heterobilayers with both stacking orders obtained on a single device. The sharp difference of interlayer excitons induced by the stacking orders was unambiguously identified, including emission wavelength, valley polarization, and temperature dependence of quantum yield. This method provides a flexible platform to study stacking order dependence of heterobilayer excitons, and can be readily applied to explore the layer hybridization, strong correlations, and exciton diffusion that are sensitive to stacking order.