Misorientation‐Angle‐Dependent Phase Transformation in van der Waals Multilayers via Electron‐Beam Irradiation

Misorientation‐angle dependence on layer thickness is an intriguing feature of van der Waals materials, which causes stark optical gain and electrical transport modulation. However, the influence of misorientation angle on phase transformation is not determined yet. Herein, this phenomenon in a MoS2...

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Bibliographic Details
Published in:Advanced materials (Weinheim) 2018-05, Vol.30 (20), p.e1706864-n/a
Main Authors: Kim, Un Jeong, Lee, Hyangsook, Lee, Woojin, Jeong, Hye Yun, Kim, Hyun, Han, Gang Hee, Lee, Hyo Sug, Park, Yeonsang, Roh, Young‐Geun, Lee, Young Hee, Lee, Eunha, Hwang, Sung Woo
Format: Article
Language:English
Subjects:
e‐beam irradiation
Irradiation
Materials science
Microstructure
Misalignment
misorientation angle
Molybdenum disulfide
MoS2
Multilayers
phase transformation
Phase transitions
Stacking
Thickness
Transmission electron microscopy
van der Waals multilayers
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Summary:Misorientation‐angle dependence on layer thickness is an intriguing feature of van der Waals materials, which causes stark optical gain and electrical transport modulation. However, the influence of misorientation angle on phase transformation is not determined yet. Herein, this phenomenon in a MoS2 multilayer via in situ electron‐beam irradiation is reported. An AA′‐stacked MoS2 bilayer undergoes structural transformation from the 2H semiconducting phase to the 1T′ metallic phase, similar to a MoS2 monolayer, which is confirmed via in situ transmission electron microscopy. Moreover, non‐AA′ stacking, which has no local AA′ stacking order in the Moiré pattern, does not reveal such a phase transformation. While a collective sliding motion of chalcogen atoms easily occurs during the transformation in AA′ stacking, in non‐AA′ stacking it is suppressed by the weak van der Waals strength and by the chalcogen atoms interlocked at different orientations, which disfavor their kinetics by the increased entropy of mixing. The influence of misorientation angle on phase transformation of non‐AA′ stacking with no local AA′ stacking order does not reveal phase transformation from 2H to 1T in contrast to AA′‐stacked MoS2. In non‐AA′ stacking, a collective sliding motion of chalcogen atoms is suppressed by the weak van der Waals strength and by the chalcogen atoms interlocked at different orientations.
ISSN:0935-9648
1521-4095
DOI:10.1002/adma.201706864