有機ポリマーによる２次元物質の新奇構造制御を実現～分子のチカラで不安定な構造を「安定化」する～

2025-05-15 東京大学

本研究で提案した結晶構造変化のイメージ

＜関連情報＞

• https://www.c.u-tokyo.ac.jp/info/news/topics/20250515140000.html
• https://pubs.acs.org/doi/10.1021/jacs.5c02099

有機エンラップメントによる1T′-MoS2の相エンジニアリング Phase Engineering of 1T′-MoS2 via Organic Enwrapment

Keigo Matsuyama,Limi Chen,Kohei Aso,Kaito Kanahashi,Kosuke Nagashio,Yoshifumi Oshima,and Daisuke Kiriya
Journal of the American Chemical Society  Published: May 7, 2025
DOI:https://doi.org/10.1021/jacs.5c02099

Abstract

Molybdenum disulfide (MoS₂) is a layered material known to show various phases. Most studies on it have focused on its semiconductor phase, but it is known to also have a metallic 1T′ phase. This 1T′ phase has also drawn attention as a quantum spin Hall phase, but the 1T′ phase is metastable, and methods for transforming or stabilizing it are still challenging. This Communication demonstrates a method for effectively transforming the monolayer or the topmost layer of multilayer semiconductor MoS₂ (the 1H or 2H phase) into the 1T′ phase via ultraviolet-ozone (UVO) treatment, followed by polymer enwrapment of the MoS₂ surface. UVO induces the transformation of the 1H (2H) phase into the 1T′ phase, but the generated phase is unstable. The enwrapment procedure with the polymer poly-l-lysine was found to be effective in transforming the 1H (2H) phase into the 1T′ phase and stabilizing it. Moreover, this procedure transformed only the topmost layer and generated a vertical 1T′/2H heterostructure in multilayer cases. This study shows the high potential of surface organic chemical procedures to control the phases in 2D transition metal dichalcogenides.