Multiple 2D Phase Transformations in Monolayer Transition Metal Chalcogenides
Multiple 2D Phase Transformations in Monolayer Transition Metal Chalcogenides
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DOI：
10.1002/adma.202200643
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发表时间：
2022-04-09
影响因子：
29.4
通讯作者：
Suenaga, Kazu
中科院分区：
文献类型：
--
作者：
Hong, Jinhua;Chen, Xi;Suenaga, Kazu
相变是材料科学的核心，因为它允许控制具有所需性质的固体的结构相。长期以来，利用设计好的界面和成分在纳米尺度上操纵晶体中的相变一直是一个挑战。在这里，在原位电子显微镜制造新的二维相具有不同的化学计量在单层二硫化钼和MoSe 2。观察到MoS_2 → Mo_4S_6和MoSe_2 → Mo_6Se_6的多相转变，这些转变具有原子级的尖锐边界。它们的原子机制被确定为硫族元素2 H 1 T滑动，阳离子移位，和相称的晶格重构，导致直接带隙减小，甚至是超导体-金属过渡。这些结果将是一个范例的多相异质结构的控制组成和尖锐的界面，这将指导未来的相工程电子学和光电子学的金属硫族化物的操作。
Phase transformation lies at the heart of materials science because it allows for the control of structural phases of solids with desired properties. It has long been a challenge to manipulate phase transformations in crystals at the nanoscale with designed interfaces and compositions. Here in situ electron microscopy is employed to fabricate novel 2D phases with different stoichiometries in monolayer MoS2 and MoSe2. The multiphase transformations: MoS2 -> Mo4S6 and MoSe2 -> Mo6Se6 which are highly localized with atomically sharp boundaries are observed. Their atomic mechanisms are determined as chalcogen 2H 1T sliding, cation shift, and commensurate lattice reconstructions, resulting in decreasing direct bandgaps and even a semiconductor-metal transition. These results will be a paradigm for the manipulation of multiphase heterostructures with controlled compositions and sharp interfaces, which will guide the future phase engineered electronics and optoelectronics of metal chalcogenides.