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dc.rights.licenseRestricted to current Rensselaer faculty, staff and students. Access inquiries may be directed to the Rensselaer Libraries.
dc.contributorKoratkar, Nikhil A. A.
dc.contributorGall, Daniel
dc.contributorShi, Yunfeng
dc.contributorTerrones, H. (Humberto)
dc.contributorLu, T.-M. (Toh-Ming), 1943-
dc.contributor.authorChow, Philippe K.
dc.date.accessioned2021-11-03T08:32:24Z
dc.date.available2021-11-03T08:32:24Z
dc.date.created2016-02-26T09:06:44Z
dc.date.issued2015-12
dc.identifier.urihttps://hdl.handle.net/20.500.13015/1611
dc.descriptionDecember 2015
dc.descriptionSchool of Engineering
dc.description.abstractThe ever-evolving symbiosis between mankind and nanoelectronics-driven technology pushes the limits of its constituent materials, largely due to the dominance of undesirable hetero-interfacial physiochemical behavior at the few-nanometer length scale, which dominates over bulk material characteristics. Driven by such instabilities, research into two-dimensional (2D) van der Waals-layered materials (e.g. graphene, transition metal dichalcogenides (TMDCs), boron nitride), which have characteristically inert surface chemistry, has virtually exploded over the past few years. The discovery of an indirect- to direct-gap conversion in semiconducting group-VI TMDCs (e.g. MoS2) upon thinning to a single atomic layer provided the critical link between metallic and insulating 2D materials. While proof-of-concept demonstrations of single-layer TMDC-based devices for visible-range photodetection, light-emission and solar energy conversion have showed promising results, the exciting qualities are downplayed by poorly-understood defectinduced photocarrier traps, limiting the best-achieved external quantum efficiencies to approximately ~1%.
dc.description.abstractThe results in this thesis shed light on the role of defects on atomically-thin TMDC optical behavior and point to yet-unexplored opportunities for further fundamental study and practical use of defects, which will expectedly benefit the development of scalable TMDC-based optoelectronic devices.
dc.description.abstractThis thesis explores the behavior of defects in atomically-thin TMDC layers in response to optical stimuli using a combination of steady-state photoluminescence, reflectance and Raman spectroscopy at room-temperature. By systematically varying the defect density using plasma-irradiation techniques, an unprecedented room-temperature defect-induced monolayer PL feature was discovered. High-resolution transmission electron microscopy correlated the defect-induced PL with plasma-generation of sulfur vacancy defects while reflectance measurements indicate defect-induced sub-bandgap light absorption. Excitation intensity-dependent PL measurements and exciton rate modeling further help elucidate the origin of the defect-induced PL response and highlights the role of non-radiative recombination on exciton conversion processes.
dc.language.isoENG
dc.publisherRensselaer Polytechnic Institute, Troy, NY
dc.relation.ispartofRensselaer Theses and Dissertations Online Collection
dc.subjectMaterials engineering
dc.titleDefect-induced optoelectronic response in single-layer group-VI transition-metal dichalcogenides
dc.typeElectronic thesis
dc.typeThesis
dc.digitool.pid177041
dc.digitool.pid177043
dc.digitool.pid177044
dc.rights.holderThis electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
dc.description.degreePhD
dc.relation.departmentDept. of Materials Science and Engineering


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