Remote Lightening and Ultrafast Transition: Intrinsic Modulation of Exciton Spatiotemporal Dynamics in Monolayer MoS2

摘要

Devices operating with excitons have promising prospects for overcoming the dilemma of response time and integration in current generation of electron- or/and photon-based elements and devices. Although the intrinsic properties including edges, grain boundaries, and defects of atomically thin semiconductors have been demonstrated as a powerful tool to adjust the bandgap and exciton energy, investigating the intrinsic modulation of spatiotemporal dynamics still remains challenging on account of the short exciton diffusion length. Here, we achieve the attractive remote lightening phenomenon, in which the emission region could be far away (up to 14.6 mu m) from the excitation center, by utilizing a femtosecond laser with ultrahigh peak power as excitation source and the edge region with high photoluminescence efficiency as a bright emitter. Furthermore, the ultrafast transition between exciton and trion is demonstrated, which provides insight into the intrinsic modulation on populations of exciton and trion states. The complete cascaded physical scenario of exciton spatiotemporal dynamics is eventually established. This work can refresh our perspective on the spatial nonuniformities of CVD-grown atomically thin semiconductors and provide important implications for developing durable and stable excitonic devices in the future.