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Atomically Resolving Polymorphs and Crystal Structures of In2Se3
journal contribution
posted on 2019-12-12, 17:42 authored by Lixuan Liu, Jiyu Dong, Junquan Huang, Anmin Nie, Kun Zhai, Jianyong Xiang, Bochong Wang, Fusheng Wen, Congpu Mu, Zhisheng Zhao, Yongji Gong, Yongjun Tian, Zhongyuan LiuThe structures of the various phases endow In2Se3 unique properties as well as a broad range of potential
applications.
However, the controversy on the structures of In2Se3 strongly hinders the exploitation of its properties and potentially
gives rise to misdirection of its applications. Here, taking advantage
of state-of-the-art aberration-corrected scanning transmission electron
microscopy, we demonstrate the atomic-scale structures of lab-created
and purchased In2Se3 compounds. Six phases in
three polymorphs at room temperature have been observed among all
the samples, which include 2H and 3R α-In2Se3, 1T, 2H, and 3R β-In2Se3, and
none-layered γ-In2Se3. Raman spectra are
directly correlated to individual In2Se3 phases,
providing fingerprints for identifying various phases of In2Se3. In addition, obvious out-of-plane ferroelectricity
of 2H α-In2Se3 was also observed by piezoresponse
force microscopy, enabling its potential application in ferroelectric
devices.