heterostructures

Long lived interlayer excitons in transition metal dichalcogenide heterobilayers hold promise for applications from high temperature exciton condensates to nano-lasers with extended spatial coherence and other 2D optoelectronic devices. However, fundamental properties of interlayer excitons, their relaxation processes, and the mechanism for their formation through interlayer charge tunneling are still poorly understood. Furthermore, new methods for control of interlayer exciton emission and the associated nonradiative decay pathways are desired to establish high temperature exciton condensation and coherent emission. Here, we use a configurable nano-optical cavity based on a plasmonic scanning probe tip to quantify the interlayer exciton lifetime of (39 +/- 8) ps and charge transfer rate of (80 +/- 20) fs at room temperature. Further, using tip-sample force perturbation with deep sub-nm precision, we actively control interlayer exciton formation and tune the competition between nonradiative charge transfer and Purcell enhancement. We discuss the extension of this tip nano-cavity approach to low and variable temperature modalities for nano-spectroscopy, imaging, and control from dark excitons to localized states.