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Adv Sci (Weinh). 2018 Dec 20;6(5):1801810. doi: 10.1002/advs.201801810. eCollection 2019 Mar 6.

Weak Interlayer Interaction in 2D Anisotropic GeSe2.

Yang Y1,2, Wang X3, Liu SC2,4, Li Z3, Sun Z5, Hu C5, Xue DJ2,4, Zhang G1, Hu JS2,4.

Author information

1
Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics Peking University Beijing 100871 China.
2
Beijing National Laboratory for Molecular Sciences (BNLMS) CAS Key Laboratory of Molecular Nanostructure and Nanotechnology CAS Research/Education Center for Excellence in Molecule Science Institute of Chemistry Chinese Academy of Science Beijing 100190 China.
3
School of Material and Chemical Engineering Tongren University Tongren 554300 China.
4
HuSchool of Chemical Sciences University of the Chinese Academy of Sciences Beijing 100049 China.
5
State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University Tianjin 300072 China.

Abstract

Germanium diselenide (GeSe2) has recently emerged as a new member of in-plane anisotropic 2D materials, notable for its wide bandgap of 2.74 eV, excellent air stability, and high performance in polarization-sensitive photodetection. However, the interlayer interaction in GeSe2 has never been reported, which usually plays an important role in layer-number-dependent physical properties. Here, the interlayer coupling in GeSe2 is systematically investigated from theory to experiment. Unexpectedly, all of density functional theory (DFT) calculations about layer-dependent band structures, cleavage energy, binding energy, translation energy, and interlayer differential charge density demonstrate the much weaker interlayer interaction in GeSe2 when compared with black phosphorus (BP). Furthermore, both thickness-dependent and temperature-dependent Raman spectra of GeSe2 flakes, which exhibit no detectable changes of Raman peaks with the increase in thickness and a small first-order temperature coefficient of -0.0095 cm-1 K-1, respectively, experimentally confirm the weakly coupled layers in GeSe2. The results establish GeSe2 as an unusual member of in-plane anisotropic 2D materials with weak interlayer interaction.

KEYWORDS:

binding energy; cleavage energy; germanium diselenide; interlayer interactions; translation energy

Conflict of interest statement

The authors declare no conflict of interest.

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