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dc.contributor.authorLiu, Song
dc.contributor.authorLiu, Tao
dc.contributor.authorGuo, Na
dc.contributor.authorZhang, Chun
dc.contributor.authorGaraj, Slaven
dc.contributor.authorBogaert, Kevin Christopher
dc.contributor.authorGradecak, Silvija
dc.date.accessioned2019-03-01T20:02:07Z
dc.date.available2019-03-01T20:02:07Z
dc.date.issued2018-08
dc.date.submitted2018-05
dc.identifier.issn2045-2322
dc.identifier.urihttp://hdl.handle.net/1721.1/120699
dc.description.abstractTwo-dimensional (2D) transition metal dichalcogenides can be alloyed by substitution at the metal atom site with negligible effect on lattice strain, but with significant influence on optical and electrical properties. In this work, we establish the relationship between composition and optical properties of the MoxW1−xS2 alloy by investigating the effect of continuously-varying composition on photoluminescence intensity. We developed a new process for growth of two-dimensional MoxW1−xS2 alloys that span nearly the full composition range along a single crystal, thus avoiding any sample-related heterogeneities. The graded alloy crystals were grown using a diffusion-based chemical vapor deposition (CVD) method that starts by synthesizing a WS2 crystal with a graded point defect distribution, followed by Mo alloying in the second stage. We show that point defects promote the diffusion and alloying, as confirmed by Raman and photoluminescence measurements, density functional theory calculations of the reaction path, and observation that no alloying occurs in CVD-treated exfoliated crystals with low defect density. We observe a significant dependence of the optical quantum yield as a function of the alloy composition reaching the maximum intensity for the equicompositional Mo0.5W0.5S2 alloy. Furthermore, we map the growth-induced strain distribution within the alloyed crystals to decouple composition and strain effects on optical properties: at the same composition, we observe significant decrease in quantum yield with induced strain. Our approach is generally applicable to other 2D materials as well as the optimization of other composition-dependent properties within a single crystal.en_US
dc.publisherNature Publishing Groupen_US
dc.relation.isversionofhttp://dx.doi.org/10.1038/s41598-018-31220-zen_US
dc.rightsCreative Commons Attribution 4.0 International licenseen_US
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en_US
dc.sourceScientific Reportsen_US
dc.titleTwo-Dimensional MoxW1−xS2 Graded Alloys: Growth and Optical Propertiesen_US
dc.typeArticleen_US
dc.identifier.citationBogaert, Kevin et al. “Two-Dimensional MoxW1−xS2 Graded Alloys: Growth and Optical Properties.” Scientific Reports 8, 1 (August 2018): 12889 © 2018 The Author(s)en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Materials Science and Engineeringen_US
dc.contributor.mitauthorBogaert, Kevin Christopher
dc.contributor.mitauthorGradecak, Silvija
dc.relation.journalScientific Reportsen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dc.date.updated2019-02-15T16:12:07Z
dspace.orderedauthorsBogaert, Kevin; Liu, Song; Liu, Tao; Guo, Na; Zhang, Chun; Gradečak, Silvija; Garaj, Slavenen_US
dspace.embargo.termsNen_US
dc.identifier.orcidhttps://orcid.org/0000-0001-8647-0246
mit.licensePUBLISHER_CCen_US


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