Zhou Jun, Huang Haojie, Zhao Zihan, Dou Zhenglong, Zhou Li, Zhang Tiantian, Huang Zhiheng, Feng Yibiao, Shi Dongxia, Liu Nan, Yang Jian, Nie J C, Wang Ququan, Dong Jichen, Liu Yunqi, Dou Ruifen, Xue Qikun
School of Physics and Astronomy, Beijing Normal University, Beijing, 100875, P. R. China.
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
Adv Mater. 2024 Sep;36(38):e2408227. doi: 10.1002/adma.202408227. Epub 2024 Jul 28.
Moiré superlattices, composed of two layers of transition metal dichalcogenides with a relative twist angle, provide a novel platform for exploring the correlated electronic phases and excitonic physics. Here, a gas-flow perturbation chemical vapor deposition (CVD) approach is demonstrated to directly grow MoS bilayer with versatile twist angles. It is found that the formation of twisted bilayer MoS homostructures sensitively depends on the gas-flow perturbation modes, correspondingly featuring the nucleation sites of the second layer at the same (homo-site) as or at the different (hetero-site) from that of the first layer. The commensurate twist angle of ≈22° in homo-site nucleation strategy accounts for ≈16% among the broad range of twist angles due to its low formation energy, which is in consistence with the theoretical calculation. More importantly, moiré interlayer excitons with the enhanced photoluminescence (PL) intensity and the prolonged lifetime are evidenced in the twisted bilayer MoS with a commensurate angle of 22°, which is owing to the reason that the strong moiré potential facilitates the interlayer excitons to be trapped in the moiré superlattices. The work provides a feasible route to controllably built twisted MoS homostructures with strong moiré potential to investigate the correlated physics in twistronics systems.
由两层具有相对扭转角的过渡金属二硫属化物组成的莫尔超晶格，为探索关联电子相和激子物理提供了一个新的平台。在此，展示了一种气流扰动化学气相沉积（CVD）方法，用于直接生长具有多种扭转角的双层MoS。发现扭曲双层MoS同质结构的形成敏感地依赖于气流扰动模式，相应地其第二层的成核位点与第一层相同（同位点）或不同（异位点）。同位点成核策略中约22°的匹配扭转角因其形成能低，在广泛的扭转角范围内约占16%，这与理论计算一致。更重要的是，在具有22°匹配角的扭曲双层MoS中证实了具有增强的光致发光（PL）强度和延长寿命的莫尔层间激子，这是因为强莫尔势有助于层间激子被困在莫尔超晶格中。这项工作为可控构建具有强莫尔势的扭曲MoS同质结构以研究扭曲电子学系统中的关联物理提供了一条可行的途径。
