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Geometry Dependent Plasmonic Activities of a Self-assembled Hexagonal Lattice and a Periodic Hexagonal Lattice with Gold Nanopillars
Thesis - University Access Only
Master of Science (MS)
Department / School
Electrical Engineering and Computer Science
Mahdi Farrokh Baroughi
Metal nanostructures play a crucial role in the emerging field of nanotechnology because they overcome the diffraction limitation. Plasmonic activities in metal nanostructures have the ability to scatter and absorb light at nanometer dimensions. There are several types of nanofabrication techniques that can make accurately sized structures but they are slow and expensive. Whereas, self-assembly technique is a high throughput and low cost process. There is a need to understand whether a self-assembled hexagonal lattice can replace the more expensive fabrication method for a number of applications. The objective of this thesis was to develop a scalable and cost-effective self-assembled hexagonal lattice and analyze its viability for replacing plasmonic lattices made using lithography. Localized plasmon resonance is non-propagating excitation of conduction electrons in metallic structures coupled with the electromagnetic waves. Plasmonic activity in the metal nanostructures depends on their geometrical parameters. Metal nanostructures are used to guide and manipulate light at the nanoscale. Silica nanobeads were used to obtain real values for nanopillar centers which were required to develop a computer algorithm to create replicas of a self-assembled hexagonal lattice. A simulation tool, EM Explorer, was used to study the plasmonic activities of the self-assembled hexagonal lattice and a periodic hexagonal lattice. Self-assembled hexagonal lattices were fabricated using silica nanobead etching masks, reactive ion etching and thermal evaporation of the metal layer. The optimum geometrical parameters for the selfassembled hexagonal lattice were d = 365 nm and h = 70 nm. A self-assembled hexagonal lattice had average electric field intensity 19 times greater than that of incident light and 23.9 times greater than that for a periodic hexagonal lattice and 60% wider resonant bandwidth. This indicates self-assembled hexagonal lattices are scalable and could be a low cost alternative to electron beam lithography. Future research can include measurement of upconversion enhancement by coating a self-assembled hexagonal lattice with upconversion nanoparticles in PMMA over.
Library of Congress Subject Headings
Includes bibliographical references (pages 104-111)
Number of Pages
South Dakota State University
In Copyright - Educational Use Permitted
Dachhepati, Dilip, "Geometry Dependent Plasmonic Activities of a Self-assembled Hexagonal Lattice and a Periodic Hexagonal Lattice with Gold Nanopillars" (2013). Electronic Theses and Dissertations. 1403.