Room-Temperature Ferroelectricity in Hexagonally Layered α-In2Se3 Nanoflakes down to the Monolayer Limit

Fei Xue*, Weijin Hu, Ko Chun Lee, Li Syuan Lu, Junwei Zhang, Hao Ling Tang, Ali Han, Wei Ting Hsu, Shaobo Tu, Wen-Hao Chang, Chen Hsin Lien, Jr Hau He, Zhidong Zhang, Lain Jong Li, Xixiang Zhang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

245 Scopus citations


2D ferroelectric material has emerged as an attractive building block for high-density data storage nanodevices. Although monolayer van der Waals ferroelectrics have been theoretically predicted, a key experimental breakthrough for such calculations is still not realized. Here, hexagonally stacking α-In2Se3 nanoflake, a rarely studied van der Waals polymorph, is reported to exhibit out-of-plane (OOP) and in-plane (IP) ferroelectricity at room temperature. Ferroelectric multidomain states in a hexagonal α-In2Se3 nanoflake with uniform thickness can survive to 6 nm. Most strikingly, the electric-field-induced polarization switching and hysteresis loop are, respectively, observed down to the bilayer and monolayer (≈1.2 nm) thicknesses, which designates it as the thinnest layered ferroelectric and verifies the corresponding theoretical calculation. In addition, two types of ferroelectric nanodevices employing the OOP and IP polarizations in 2H α-In2Se3 are developed, which are applicable for nonvolatile memories and heterostructure-based nanoelectronics/optoelectronics.

Original languageEnglish
Article number1803738
Pages (from-to)1-7
Number of pages7
JournalAdvanced Functional Materials
Issue number50
StatePublished - 12 Dec 2018


  • hexagonal α-In2Se3
  • layered 2D materials
  • monolayer
  • room-temperature ferroelectricity


Dive into the research topics of 'Room-Temperature Ferroelectricity in Hexagonally Layered α-In2Se3 Nanoflakes down to the Monolayer Limit'. Together they form a unique fingerprint.

Cite this