2026-03-05 東京大学,北陸先端科学技術大学院大学,筑波大学
液滴を用いた単層二次元半導体の折り畳みのイメージ
＜関連情報＞
- https://www.c.u-tokyo.ac.jp/info/news/topics/20260305010000.html
- https://www.cell.com/matter/abstract/S2590-2385(26)00021-4
自発的な液液相分離を介してねじれた二重層フラグメントの大量形成を促進する微小液滴の合体 Microdroplet coalescence driving mass formation of twisted bilayer fragments via spontaneous liquid-liquid phase separation
Shotaro Yotsuya ∙ Takahiko Endo ∙ Yasumitsu Miyata ∙ … ∙ Yaheng Wang ∙ Kazunori Serita, ∙ Daisuke Kiriya
Matter Published:March 4, 2026
DOI:https://doi.org/10.1016/j.matt.2026.102658
Progress and potential
Moiré structures have gained significant attention because their crystalline periodicity enables the modulation of their internal electronic states. However, conventional approaches to constructing stacked bilayers utilize mechanical stacking, which generates moiré structures individually. Here, droplet-assisted methods provide high scalability for preparing folded, stacked bilayer structures. Such methods involve spontaneous micron-scale droplet formation through a non-equilibrium process via the evaporation of the matrix solvent. Because the droplet size is sufficiently small compared to the monolayer flakes, the shear forces at the interface induce folding in the material. In addition, controlling the stacking angle is crucial for tuning the periodicity of moiré structures; this work suggests the potential to achieve this through a combination of fabrication techniques to direct the droplet motion. This approach will be useful for systematically creating twisted bilayer structures and exploring their emergent properties.
Highlights
- Liquid-liquid phase separation is applied to generate micron-scale droplets
- The droplets move and coalesce on monolayers, inducing the folding phenomenon
- Folded bilayer MoS2 demonstrates moiré structure
- Folding angle controllability of ∼24% was achieved by designing the sample shape with etching
Summary
The stacking of monolayers to form a twisted bilayer has attracted attention because of the emergent properties of moiré patterns. However, the current process of forming twisted bilayers involves mechanically repeating the pick-up and restacking of monolayers, which is a nonscalable method. In this study, we developed a method for mass production of stacking twisted bilayers using the coalescence of unique droplets. The droplets were formed via the liquid-liquid phase separation phenomenon, in which droplets spontaneously form in a uniform solution. The droplets move and coalesce on the monolayers, inducing folding of the monolayer and enabling the mass production of twisted stacked bilayers.
