TY  - JOUR
AU  - Wang, Xudong
AU  - Tan, Jieling
AU  - Han, Chengqian
AU  - Wang, Jiang-Jing
AU  - Lu, Lu
AU  - Du, Hongchu
AU  - Jia, Chun-Lin
AU  - Deringer, Volker L.
AU  - Zhou, Jian
AU  - Zhang, Wei
TI  - Sub-Angstrom Characterization of the Structural Origin for High In-Plane Anisotropy in 2D GeS 2
JO  - ACS nano
VL  - 14
IS  - 4
SN  - 1936-086X
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2020-02709
SP  - 4456 - 4462
PY  - 2020
AB  - Materials with layered crystal structures and high in-plane anisotropy, such as black phosphorus, present unique properties and thus promise for applications in electronic and photonic devices. Recently, the layered structures of GeS2 and GeSe2 were utilized for high-performance polarization-sensitive photodetection in the short wavelength region due to their high in-plane optical anisotropy and wide band gap. The highly complex, low-symmetric (monoclinic) crystal structures are at the origin of the high in-plane optical anisotropy, but the structural nature of the corresponding nanostructures remains to be fully understood. Here, we present an atomic-scale characterization of monoclinic GeS2 nanostructures and quantify the in-plane structural anisotropy at the sub-angstrom level in real space by Cs-corrected scanning transmission electron microscopy. We elucidate the origin of this high in-plane anisotropy in terms of ordered and disordered arrangement of [GeS4] tetrahedra in GeS2 monolayers, through density functional theory (DFT) calculations and orbital-based bonding analyses. We also demonstrate high in-plane mechanical, electronic, and optical anisotropies in monolayer GeS2 and envision phase transitions under uniaxial strain that could potentially be exploited for nonvolatile memory applications.
LB  - PUB:(DE-HGF)16
C6  - pmid:32275386
UR  - <Go to ISI:>//WOS:000529895500065
DO  - DOI:10.1021/acsnano.9b10057
UR  - https://juser.fz-juelich.de/record/878240
ER  -