Dhakal Krishna P, Ghimire Ganesh, Chung Kyungwha, Duong Dinh Loc, Kim Sung Wng, Kim Jeongyong
Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea.
Center for Integrated Nanostructure Physics , Institute for Basic Science , Suwon 16419 , Republic of Korea.
ACS Nano. 2019 Dec 24;13(12):14437-14446. doi: 10.1021/acsnano.9b08037. Epub 2019 Nov 26.
Structural phase transitions in layered two-dimensional (2D) materials are of significant interest owing to their ability to exist in multiple metastable states with distinctive properties. However, phase transition in bulk MoS by nondestructive electron infusion has not yet been realized. In this study, we report the 2H to 1T' phase transition and in-between intermediates in bulk MoS using MoS/[CaN]·e heterostructures, in which kinetic free electrons were directly injected into MoS. We observed various phases in MoS ranging from heavily doped 2H to a distorted lattice state and then on to a complete 1T' state. Snapshots of the multiphase transition were captured by extraordinary Raman shift and bandgap reduction and were further elucidated by theoretical calculations. We also observed a weakening in interlayer coupling in the vicinity of the metallic regime, which led to an unusually strong photoluminescence emission, suggesting light-efficient bulk MoS. Our results thus suggest the optoelectronic applications that can fully utilize the multiphase transition of bulk 2D materials.
层状二维（2D）材料中的结构相变备受关注，因为它们能够存在于具有独特性质的多个亚稳态。然而，通过无损电子注入实现块状MoS₂的相变尚未实现。在本研究中，我们报道了使用MoS₂/[CaN]·e异质结构在块状MoS₂中实现的2H到1T'相变以及中间的过渡态，其中动力学自由电子被直接注入到MoS₂中。我们观察到MoS₂中从重掺杂的2H到晶格畸变状态再到完全的1T'状态的各种相。多相转变的瞬间通过异常拉曼位移和带隙减小被捕捉到，并通过理论计算进一步阐明。我们还观察到在金属态附近层间耦合减弱，这导致了异常强烈的光致发光发射，表明块状MoS₂具有高效的光。我们的结果因此表明了可以充分利用块状二维材料多相转变的光电子应用。
