Carbon nanotubes as materials in nanotechnology

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dc.contributor.advisor Greer, James C. en
dc.contributor.author Jones, Sarah L. T.
dc.date.accessioned 2013-12-18T16:45:17Z
dc.date.available 2013-12-18T16:45:17Z
dc.date.issued 2013
dc.date.submitted 2013
dc.identifier.citation Jones, S. L., 2013. Carbon nanotubes as materials in nanotechnology. PhD Thesis, University College Cork. en
dc.identifier.endpage 148
dc.identifier.uri http://hdl.handle.net/10468/1286
dc.description.abstract Carbon 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.sponsorship Irish Research Council for Science Engineering and Technology (IRCSET Postgraduate Research Scholarship (RS 2000246)) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2013, Sarah L. Jones en
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/3.0/ en
dc.subject Defects en
dc.subject Doping en
dc.subject Carbon nanotubes en
dc.subject Density functional theory (DFT) en
dc.subject.lcsh Nanotubes en
dc.subject.lcsh Nanoelectronics en
dc.title Carbon nanotubes as materials in nanotechnology en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PhD (Science) en
dc.internal.availability Full text available en
dc.check.info No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council for Science, Engineering and Technology en
dc.description.status Not peer reviewed en
dc.internal.school Chemistry en
dc.internal.school Tyndall National Institute en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
ucc.workflow.supervisor jim.greer@tyndall.ie
dc.internal.conferring Autumn Conferring 2013 en


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