Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers

We study the atomic structure and dynamics of defects and grain boundaries in monolayer Pd2Se3 using annular dark field scanning transmission electron microscopy. The Pd2Se3 monolayers are reproducibly created by thermally induced phase transformation of few-layered PdSe2 films in an in situ heating...

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Main Authors: Chen, J, Ryu, G, Sinha, S, Warner, J
Format: Journal article
Language:English
Published: American Chemical Society 2019
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author Chen, J
Ryu, G
Sinha, S
Warner, J
author_facet Chen, J
Ryu, G
Sinha, S
Warner, J
author_sort Chen, J
collection OXFORD
description We study the atomic structure and dynamics of defects and grain boundaries in monolayer Pd2Se3 using annular dark field scanning transmission electron microscopy. The Pd2Se3 monolayers are reproducibly created by thermally induced phase transformation of few-layered PdSe2 films in an in situ heating holder in the TEM to promote Se loss. A variety of point vacancies, one-dimensional defects, grain boundaries (GBs), and defect ring complexes are directly observed in monolayer Pd2Se3, which show a series of dynamics triggered by electron beam irradiation. High mobility of vacancies leads to self-healing of point vacancies by migration to the edge and subsequent edge etching under beam irradiation. Specific defects for Pd2Se3 are stabilized by the formation of Se–Se bonds, which can shift in a staggered way to buffer strain, forming a wave-like one-dimensional defect. Bond rotations are also observed and play an important role in defect and grain boundary dynamics in Pd2Se3 during vacancy production. The GBs form in a meandering pathway and migrate by a sequence of Se–Se bond rotations without large-scale vacancy formation. In the GB corners and tilted GBs, other highly symmetric vacancy defects also occur to adapt to the orientation change. These results give atomic level insights into the defects and grain boundaries in Pd2Se3 2D monolayers.
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spelling oxford-uuid:478797c3-5503-4436-ba55-962b24a4aed32022-03-26T15:20:33ZAtomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayersJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:478797c3-5503-4436-ba55-962b24a4aed3EnglishSymplectic Elements at OxfordAmerican Chemical Society2019Chen, JRyu, GSinha, SWarner, JWe study the atomic structure and dynamics of defects and grain boundaries in monolayer Pd2Se3 using annular dark field scanning transmission electron microscopy. The Pd2Se3 monolayers are reproducibly created by thermally induced phase transformation of few-layered PdSe2 films in an in situ heating holder in the TEM to promote Se loss. A variety of point vacancies, one-dimensional defects, grain boundaries (GBs), and defect ring complexes are directly observed in monolayer Pd2Se3, which show a series of dynamics triggered by electron beam irradiation. High mobility of vacancies leads to self-healing of point vacancies by migration to the edge and subsequent edge etching under beam irradiation. Specific defects for Pd2Se3 are stabilized by the formation of Se–Se bonds, which can shift in a staggered way to buffer strain, forming a wave-like one-dimensional defect. Bond rotations are also observed and play an important role in defect and grain boundary dynamics in Pd2Se3 during vacancy production. The GBs form in a meandering pathway and migrate by a sequence of Se–Se bond rotations without large-scale vacancy formation. In the GB corners and tilted GBs, other highly symmetric vacancy defects also occur to adapt to the orientation change. These results give atomic level insights into the defects and grain boundaries in Pd2Se3 2D monolayers.
spellingShingle Chen, J
Ryu, G
Sinha, S
Warner, J
Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title_full Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title_fullStr Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title_full_unstemmed Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title_short Atomic structure and dynamics of defects and grain boundaries in 2D Pd2Se3 monolayers
title_sort atomic structure and dynamics of defects and grain boundaries in 2d pd2se3 monolayers
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AT ryug atomicstructureanddynamicsofdefectsandgrainboundariesin2dpd2se3monolayers
AT sinhas atomicstructureanddynamicsofdefectsandgrainboundariesin2dpd2se3monolayers
AT warnerj atomicstructureanddynamicsofdefectsandgrainboundariesin2dpd2se3monolayers