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dc.contributor.authorGogoi, Pranjal Kumar
dc.contributor.authorHu, Zhenliang
dc.contributor.authorWang, Qixing
dc.contributor.authorCarvalho, Alexandra
dc.contributor.authorSchmidt, Daniel
dc.contributor.authorYin, Xinmao
dc.contributor.authorChang, Yung-Huang
dc.contributor.authorLi, Lain-Jong
dc.contributor.authorSow, Chorng Haur
dc.contributor.authorNeto, A. H. Castro
dc.contributor.authorBreese, Mark B. H.
dc.contributor.authorRusydi, Andrivo
dc.contributor.authorWee, Andrew T. S.
dc.date.accessioned2017-10-05T12:47:10Z
dc.date.available2017-10-05T12:47:10Z
dc.date.issued2017-08-16
dc.identifier.citationGogoi PK, Hu Z, Wang Q, Carvalho A, Schmidt D, et al. (2017) Oxygen Passivation Mediated Tunability of Trion and Excitons in MoS2. Physical Review Letters 119. Available: http://dx.doi.org/10.1103/PhysRevLett.119.077402.
dc.identifier.issn0031-9007
dc.identifier.issn1079-7114
dc.identifier.doi10.1103/PhysRevLett.119.077402
dc.identifier.urihttp://hdl.handle.net/10754/625822
dc.description.abstractUsing wide spectral range in situ spectroscopic ellipsometry with systematic ultrahigh vacuum annealing and in situ exposure to oxygen, we report the complex dielectric function of MoS2 isolating the environmental effects and revealing the crucial role of unpassivated and passivated sulphur vacancies. The spectral weights of the A (1.92 eV) and B (2.02 eV) exciton peaks in the dielectric function reduce significantly upon annealing, accompanied by spectral weight transfer in a broad energy range. Interestingly, the original spectral weights are recovered upon controlled oxygen exposure. This tunability of the excitonic effects is likely due to passivation and reemergence of the gap states in the band structure during oxygen adsorption and desorption, respectively, as indicated by ab initio density functional theory calculation results. This Letter unravels and emphasizes the important role of adsorbed oxygen in the optical spectra and many-body interactions of MoS2.
dc.description.sponsorshipThis work is supported by ASTAR Pharos Grant No. R-144-000-359-305 and SERC 1527000012, Singapore National Research Foundation under its Competitive Research Funding (NRF-CRP 8-2011-06 and No. R-398-000-087-281), MOE-AcRF Tier-2 (MOE2010-T2-2-121), and FRC (R-144-000-368-112), and the Medium Sized Centre Programme and CRP Grant "Novel 2D materials with tailored properties: Beyond graphene" (R-144-000-295-281). The first-principles calculations were carried out on the Centre for Advanced 2D Materials and Graphene Research Centre high-performance computing facilities.
dc.publisherAmerican Physical Society (APS)
dc.relation.urlhttps://journals.aps.org/prl/abstract/10.1103/PhysRevLett.119.077402
dc.rightsArchived with thanks to Physical Review Letters
dc.titleOxygen Passivation Mediated Tunability of Trion and Excitons in MoS2
dc.typeArticle
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalPhysical Review Letters
dc.eprint.versionPublisher's Version/PDF
dc.contributor.institutionSingapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore, 117603, , Singapore
dc.contributor.institutionDepartment of Physics, Faculty of Science, National University of Singapore, Singapore, 117542, , Singapore
dc.contributor.institutionCentre for Advanced 2D Materials, Graphene Research Centre, National University of Singapore, Singapore, 117542, , Singapore
dc.contributor.institutionDepartment of Electrophysics, National Chiao Tung University, Hsinchu, 30010, , Taiwan
dc.contributor.institutionNUSNNI-NanoCore, National University of Singapore, Singapore, 117576, , Singapore
dc.identifier.arxivid1707.06348
kaust.personLi, Lain-Jong
refterms.dateFOA2018-06-13T15:24:45Z


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