Carbon nanotubes as materials in nanotechnology

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dc.check.embargoformatNot applicableen
dc.check.infoNo embargo requireden
dc.check.opt-outNot applicableen
dc.check.reasonNo embargo requireden
dc.check.typeNo Embargo Required
dc.contributor.advisorGreer, James C.en
dc.contributor.authorJones, Sarah L. T.
dc.contributor.funderIrish Research Council for Science, Engineering and Technologyen
dc.date.accessioned2013-12-18T16:45:17Z
dc.date.available2013-12-18T16:45:17Z
dc.date.issued2013
dc.date.submitted2013
dc.description.abstractCarbon nanotubes (CNTs) are hollow tubes of sp2-hybridised carbon with diameters of the order of nanometres. Due to their unique physical properties, which include ballistic transport and high mechanical strength, they are of significant interest for technological applications. The electronic properties of CNTs are of particular interest for use as gas sensors, interconnect materials in the semi-conductor industry and as the channel material in CNT based field effect transistors. The primary difficulty associated with the use of CNTs in electronic applications is the inability to control electronic properties at the growth stage; as grown CNTs consist of a mixture of metallic and semi-conducting CNTs. Doping has the potential to solve this problem and is a focus of this thesis. Nitrogen-doped CNTs typically have defective structures; the usual hollow CNT structure is replaced by a series of compartments. Through density functional theory (DFT) calculations and experimental results, we propose an explanation for the defective structures obtained, based on the stronger binding of N to the growth catalyst in comparison to C. In real electronic devices, CNTs need to be contacted to metal, we generate the current-voltage (IV) characteristics of metal-contacted CNTs considering both the effect of dopants and the structure of the interface region on electronic properties. We find that substitutionally doped CNTs produce Ohmic contacts and that scattering at the interface is strongly influenced by structure. In addition, we consider the effect of the common vacancy defects on the electronic properties of large diameter CNTs. Defects increase scattering in the CNT, with the greatest scattering occurring for the largest defect (555777). We validate the independent scattering approximation for small diameter CNTs, which enables mean free paths in large diameter CNTs to be calculated, with a smaller mean free paths found for larger defects.en
dc.description.sponsorshipIrish Research Council for Science Engineering and Technology (IRCSET Postgraduate Research Scholarship (RS 2000246))en
dc.description.statusNot peer revieweden
dc.description.versionAccepted Version
dc.format.mimetypeapplication/pdfen
dc.identifier.citationJones, S. L., 2013. Carbon nanotubes as materials in nanotechnology. PhD Thesis, University College Cork.en
dc.identifier.endpage148
dc.identifier.urihttps://hdl.handle.net/10468/1286
dc.language.isoenen
dc.publisherUniversity College Corken
dc.rights© 2013, Sarah L. Jonesen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/en
dc.subjectDefectsen
dc.subjectDopingen
dc.subjectCarbon nanotubesen
dc.subjectDensity functional theory (DFT)en
dc.subject.lcshNanotubesen
dc.subject.lcshNanoelectronicsen
dc.thesis.opt-outfalse
dc.titleCarbon nanotubes as materials in nanotechnologyen
dc.typeDoctoral thesisen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD (Science)en
ucc.workflow.supervisorjim.greer@tyndall.ie
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