Due to its sizable direct bandgap and strong light-matter interactions, the preparation of monolayer MoS2 has attracted significant attention and intensive research efforts. However, multilayer MoS2 is largely overlooked because of its optically inactive indirect bandgap caused by interlayer coupling. It is highly desirable to modulate and decrease the interlayer coupling so that each layer in multilayer MoS2 can exhibit a monolayer-like direct-gap behavior. Here, we demonstrate the nanoprobe fabrication of LixMoS2-based multilayers exhibiting a direct bandgap and strong photoluminescence emission from tightly bound excitons and trions. The fabrication is facilitated by our newly developed Li-ion platform, featuring tip-induced Li intercalation, air stability and rewritability. Raman characterizations reveal that controlled Li intercalation effectively transforms multilayer MoS2 into the stack of multiple monolayers, leading to a 26-fold enhancement of photoluminescence, compared to a monolayer. This intercalation result is different from existing observations of transforming MoS2 multilayers into metallic phases.
Cite
@article{arxiv.2503.00474,
title = {Air-stable lithiation engineering of $\mathrm{MoS}_{2}$ for direct-bandgap multilayers},
author = {Qi Fu and Yichi Zhang and Jichuang Shen and Siyuan Hong and Jie Wang and Chen Wang and Jingyi Shen and Wei Kong and Guolin Zheng and Jun Yan and Jie Wu and Changxi Zheng},
journal= {arXiv preprint arXiv:2503.00474},
year = {2025}
}