One‐Interlayer‐Twisted Multilayer MoS2 Moiré Superlattices

• Published in: Advanced functional materials Vol. 32; no. 19
• Main Authors: Zhang, Weifeng, Hao, He, Lee, Yangjin, Zhao, Yan, Tong, Lianming, Kim, Kwanpyo, Liu, Nan
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.05.2022
• Subjects: Bilayers; Circular polarization; interlayer coupling; Interlayers; Liquid nitrogen; Materials science; Molybdenum disulfide; multilayer; Multilayers; Optical properties; Paraffins; Superlattices; Transition metal compounds; twist angle; Two dimensional materials; valley polarization
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202111529

Twist angle provides a new degree of freedom for 2D material modifications. In principle, the intrinsic properties of twisted multilayers can be regulated by twist angle between each adjacent layer and thus have greater tunability than widely studied bilayer structures. Considering its complexity, it is important to first investigate the simplest twisted multilayers with only one interface twisted. In this work, multilayer Moiré superlattices with only one twisted interface via paraffin‐assisted folding of non‐twisted stacked (highly symmetrically stacked) multilayer MoS2 are successfully fabricated, and their twist‐angle dependent optical properties are systematically studied. Compared to non‐twisted stacked multilayer MoS2, the one‐interface‐twisted multilayers show a 2–3.5 times higher PL intensity, and their interlayer coupling, indirect bandgap, and degree of circular polarization (DOCP) are tunable by twist angle. Notably, the DOCP for the one‐interface‐twisted four‐layer (folded bilayer) can reach 86%, which is the highest value ever reported for transition metal dichalcogenide homostructures above liquid nitrogen temperature. This work provides a solid base for understanding twist‐angle dependent properties of twisted multilayer 2D‐materials. Twist angle induces various Moiré‐related properties in 2D materials, but most studies only focus on bilayer systems. Here, via a folding strategy, multilayer MoS2 Moiré superlattices are fabricated whose interlayer coupling, indirect bandgap, and degree of circular polarization (DOCP) are tunable by twist angle. The highest DOCP for folded bilayer MoS2 can reach 86% above liquid nitrogen temperature.