Energy transfer driven brightening of MoS<sub>2</sub> by ultrafast polariton relaxation in microcavity MoS<sub>2</sub>/hBN/WS<sub>2</sub> heterostructures.

Hu, Zehua; Krisnanda, Tanjung; Fieramosca, Antonio; Zhao, Jiaxin; Sun, Qianlu; Chen, Yuzhong; Liu, Haiyun; Luo, Yuan et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Energy transfer is a ubiquitous phenomenon that delivers energy from a blue-shifted emitter to a red-shifted absorber, facilitating wide photonic applications. Two-dimensional (2D) semiconductors provide unique opportunities for exploring novel energy transfer mechanisms in the atomic-scale limit. Herein, we have designed a planar optical microcavity-confined MoS<sub>2</sub>/hBN/WS<sub>2</sub> heterojunction, which realizes the strong coupling among donor exciton, acceptor exciton, and cavity photon mode. This configuration demonstrates an unconventional energy transfer via polariton relaxation, brightening MoS<sub>2</sub> with a record-high enhancement factor of ~440, i.e., two-order-of-magnitude higher than the data reported to date. The polariton relaxation features a short characteristic time of ~1.3 ps, resulting from the significantly enhanced intra- and inter-branch exciton-exciton scattering. The polariton relaxation dynamics is associated with Rabi energies in a phase diagram by combining experimental and theoretical results. This study opens a new direction of microcavity 2D semiconductor heterojunctions for high-brightness polaritonic light sources and ultrafast polariton carrier dynamics.