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Fabrication and geometrical characterization of metal and metal-dielectric composite periodic nanostructures

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dc.contributor.advisor Atre, Sundar
dc.creator Bhowmik, Siddhartha
dc.date.accessioned 2009-09-23T23:16:02Z
dc.date.available 2009-09-23T23:16:02Z
dc.date.copyright 2009-06-25
dc.date.issued 2009-06-25
dc.identifier.uri http://hdl.handle.net/1957/12746
dc.description Graduation date: 2010 en
dc.description.abstract Periodic metal and metal-dielectric composite nanostructures have been of interest from the field of plasmonics and metamaterial fabrication. In order to exploit the behavior of these unique materials in the visible region of the optical spectrum, these structures need to be significantly shorter than the wavelength of response, and hence fabrication of these have posed unique challenges. One of the key fabrication aspects is the metal thin film deposition. This study has looked at key parameters in PVD which influence the grain structure and morphology, in one of the metals of interest, Ag, and further examined how these factors influence formation of these periodic nanostructures. Our findings indicate small grain sizes formed with high source-to-substrate spacing are optimal conditions for forming nanostructures with different geometries with size less than 100nm. Additionally our studies also indicate these conditions provide films with least agglomeration and a smooth texture which could have significant impact on their optical behavior. The study also looked at formation of nanostructures through different processes – (i) additive process via lift-off and electron beam lithography (EBL) and (ii) subtractive processes of ion beam milling, and reactive ion etch (RIE). This included examining three metals of interest in plasmonics- Ag, Au and Al. Our findings indicate that the optimized process is dependent on the metal systems and liftoff with EBL remains the most flexible option. RIE may be suitable for Al based systems where we form a volatile species during etch while it may not be as successful for Au and Ag. For isolated nanostructures as discussed in this paper, ion beam etch is highly dependent on grain sizes and may have some fundamental limitations in isolating structures. The structural and morphological characterization of nanostructures has also been of importance and has been carried out as part of this work with SEM, AFM, EDS, and TEM studies. The impact and application of these structures could be greatly enhanced by their formation in a flexible polymer membrane and this was also demonstrated as part of this thesis. Finally, we also present some optical data of these nanostructures where we see a difference in extinction coefficient of these structures based on both geometry and metal choice. en
dc.language.iso en_US en
dc.subject Nanofabrication en
dc.subject Plasmonic en
dc.subject Nanostructures en
dc.subject Metal en
dc.subject Composites en
dc.subject.lcsh Nanostructured materials en
dc.subject.lcsh Dielectrics en
dc.subject.lcsh Metallic composites en
dc.subject.lcsh Metallic films en
dc.title Fabrication and geometrical characterization of metal and metal-dielectric composite periodic nanostructures en
dc.type Thesis/Dissertation en
dc.degree.name Doctor of Philosophy (Ph. D.) in Materials Science en
dc.degree.level Doctoral en
dc.degree.discipline Engineering en
dc.degree.grantor Oregon State University en
dc.contributor.committeemember Ostroverkhova, Oksana
dc.contributor.committeemember Rochefort, Skip
dc.contributor.committeemember Warnes, William
dc.contributor.committeemember Hackleman, David

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