Yang Chunxia, Lin Qingyun, Sato Yuta, Gao Yanlin, Zheng Yongjia, Wang Tianyu, Ma Yicheng, Dai Wanyu, Li Wenbin, Maruyama Mina, Okada Susumu, Suenaga Kazu, Maruyama Shigeo, Xiang Rong
Department of Mechanical Engineering, The University of Tokyo, Tokyo, 113-8656, Japan.
Center of Electron Microscopy, State Key Laboratory of Silicon and Advanced Semiconductor Materials, School of Material Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
Small. 2025 Jul;21(27):e2412454. doi: 10.1002/smll.202412454. Epub 2025 Apr 3.
Two-dimensional (2D) Janus transition metal dichalcogenide (TMDC) layers with broken mirror symmetry exhibit giant Rashba splitting and unique excitonic behavior. For their one-dimensional (1D) counterparts, the Janus nanotubes possess curvature, which introduces an additional degree of freedom to break the structural symmetry. This can potentially enhance these effects or even give rise to novel properties. Moreover, Janus MSSe nanotubes (M = W, Mo), with diameters surpassing 40 Å and Se positioned externally consistently demonstrate lower energy states compared to their Janus monolayer counterparts. However, there are limited studies on the preparation of Janus nanotubes, due to the synthesis challenge and limited sample quality. In this study, we first synthesized MoS nanotubes on single-walled carbon nanotube (SWCNT) and boron nitride nanotube (BNNT) heterostructures and then explored the growth of Janus MoSSe nanotubes from MoS nanotubes at room temperature with the assistance of H plasma. The successful formation of the Janus structure is confirmed by Raman spectroscopy, and atomic structure and elemental distribution of the grown samples are further characterized by advanced electronic microscopy. The synthesis of Janus MoSSe nanotubes based on SWCNT-BNNT heterostructures paves the way for further exploration of novel properties in Janus TMDC nanotubes.
具有破镜面对称性的二维（2D）Janus过渡金属二硫属化物（TMDC）层表现出巨大的Rashba分裂和独特的激子行为。对于其一维（1D）对应物，Janus纳米管具有曲率，这引入了额外的自由度来打破结构对称性。这有可能增强这些效应，甚至产生新的特性。此外，直径超过40 Å且硒始终位于外部的Janus MSSe纳米管（M = W、Mo）与其Janus单层对应物相比，始终表现出更低的能量状态。然而，由于合成挑战和样品质量有限，关于Janus纳米管制备的研究有限。在本研究中，我们首先在单壁碳纳米管（SWCNT）和氮化硼纳米管（BNNT）异质结构上合成了MoS纳米管，然后在H等离子体的辅助下，在室温下探索了从MoS纳米管生长Janus MoSSe纳米管的过程。通过拉曼光谱证实了Janus结构的成功形成，并通过先进的电子显微镜进一步表征了生长样品的原子结构和元素分布。基于SWCNT-BNNT异质结构合成Janus MoSSe纳米管为进一步探索Janus TMDC纳米管的新特性铺平了道路。
