Exciton Dynamics and Electrical Tuning in Moiré Heterobilayers of Transition Metal Dichalcogenides

Huan-Li Meng¹, Yang-Hong Chen¹, Yi-Hsuan Sung¹, Cheng-Syuan Cai^1,2, Tzu-Chieh Chou^1,2, Ro-Ya Liu², Chih-Ming Lin¹, Shangjr Gwo¹, Wei-Ting Hsu^1*

¹Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
²National Synchrotron Radiation Research Center, Hsinchu, Taiwan

* Presenter:Wei-Ting Hsu, email:wthsu@phys.nthu.edu.tw

Transition metal dichalcogenide (TMD) heterostructures have emerged as a promising platform for developing novel optoelectronic devices. This potential is primarily attributed to their stable excitons, which exhibit strong light-matter coupling and can be controlled electrically. While considerable research has examined exciton dynamics in TMD monolayers, systematic studies on interlayer excitons in TMD moiré heterobilayers remain limited. In this work, we report distinct exciton dynamics in TMD-based moiré heterobilayers. The type-II band alignment, along with the moiré superlattice, leads to nontrivial exciton annihilation and upconversion processes. In addition, we demonstrate that exciton charged states can be significantly tuned through electrical gating. Our findings not only highlight the role of electron Coulomb interactions in exciton scattering pathways but also suggest an efficient approach for exciton manipulation.

Keywords: transition metal dichalcogenide, exciton dynamics, electrical tuning