Phase-controllable large-area two-dimensional In2Se3 and ferroelectric heterophase junction

• Published in: Nature nanotechnology Vol. 18; no. 1; pp. 55 - 63
• Main Authors: Han, Wei, Zheng, Xiaodong, Yang, Ke, Tsang, Chi Shing, Zheng, Fangyuan, Wong, Lok Wing, Lai, Ka Hei, Yang, Tiefeng, Wei, Qi, Li, Mingjie, Io, Weng Fu, Guo, Feng, Cai, Yuan, Wang, Ning, Hao, Jianhua, Lau, Shu Ping, Lee, Chun-Sing, Ly, Thuc Hue, Yang, Ming, Zhao, Jiong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2023; Nature Publishing Group
• Subjects: 140/133; 140/146; 142/126; 639/301/357/1018; 639/925/927/1007; Antiferroelectricity; Chemical synthesis; Chemical vapor deposition; Chemistry and Materials Science; Cognitive ability; Computer memory; Controllability; Electron mobility; Ferroelectric materials; Materials Science; Mica; Nanotechnology; Nanotechnology and Microengineering; Phase transitions; Polymorphism; Semiconductor devices; Substrates; Transistors
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/s41565-022-01257-3

Memory transistors based on two-dimensional (2D) ferroelectric semiconductors are intriguing for next-generation in-memory computing. To date, several 2D ferroelectric materials have been unveiled, among which 2D In 2 Se 3 is the most promising, as all the paraelectric (β), ferroelectric (α) and antiferroelectric (β′) phases are found in 2D quintuple layers. However, the large-scale synthesis of 2D In 2 Se 3 films with the desired phase is still absent, and the stability for each phase remains obscure. Here we show the successful growth of centimetre-scale 2D β-In 2 Se 3 film by chemical vapour deposition including distinct centimetre-scale 2D β′-In 2 Se 3 film by an InSe precursor. We also demonstrate that as-grown 2D β′-In 2 Se 3 films on mica substrates can be delaminated or transferred onto flexible or uneven substrates, yielding α-In 2 Se 3 films through a complete phase transition. Thus, a full spectrum of paraelectric, ferroelectric and antiferroelectric 2D films can be readily obtained by means of the correlated polymorphism in 2D In 2 Se 3 , enabling 2D memory transistors with high electron mobility, and polarizable β′–α In 2 Se 3 heterophase junctions with improved non-volatile memory performance. A chemical-vapour-deposition-based approach enables the phase-controllable synthesis of large-scale two-dimensional β-, β′- and α-In 2 Se 3 films.