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dc.contributor.advisorÖzbay, Ekmel
dc.contributor.authorCinel, Neval A
dc.date.accessioned2016-01-08T20:02:44Z
dc.date.available2016-01-08T20:02:44Z
dc.date.issued2013
dc.identifier.urihttp://hdl.handle.net/11693/16896
dc.descriptionAnkara : The Department of Electrical and Electronics Engineering and the Graduate School of Engineering and Science of Bilkent University, 2013.en_US
dc.descriptionThesis (Ph. D.) -- Bilkent University, 2013.en_US
dc.descriptionIncludes bibliographical references leaves 74-84.en_US
dc.description.abstractPlasmonics is a major branch of photonics dealing with light-matter interactions in metallic nanostructures. Plasmonic devices provide extreme confinement of electromagnetic oscillations to very small volumes beyond diffraction limit at optical frequencies. Our aim in this thesis study is to demonstrate the utilization of plasmonics for several applications such as optical localized surface plasmon resonance (LSPR) biosensor design, enhancement of signal intensity in surface enhanced Raman spectroscopy (SERS) and absorption enhancement in photodetectors. Firstly, a sensor structure that detects the changes in the refractive index of the surrounding medium by optical transmission measurements was designed. Periodic silver nano-disk arrays on sapphire substrate written by Electron-Beam Lithography (EBL) were used for this aim. Optical characterization was done through transmission/reflection measurements and supported by finite difference time domain (FDTD) simulations. The sensor was first verified by a biotinavidin bioassay. Real time binding studies showed that the sensor response was saturated within the first 30 minutes of application. Concentration dependency of the sensor structure showed an adequate response at the 1 nM-100 nM range. The refractive index sensitivity of the sensor was determined as 354 nm/RIU. The idea was finally applied to the detection of heat killed E.Coli bacteria. Promising results that indicate the possibility of using the sensor for bacteria detection was obtained. Secondly, tandem truncated nano-cones composed of Au-SiO2-Au layers that exhibit highly tunable double resonance behavior were shown to increase SERS signal intensity, for the first time. Enhancement factor (EF) calculations indicated an enhancement factor of 3.86 x107 . The double resonance design showed a 10 fold better enhancement when compared to its single resonance counterpart. This enhancement is believed to be even more prominent for applications such as NIR-SERS and Surface Enhanced Hyper Raman Scattering (SEHRS). Another SERS substrate containing dual layer, periodic, “coupled” concentric rings, separated by a dielectric spacer provided Raman signal intensity 630 times larger than plain gold film and 8 times larger than an “etched” concentric ring structure. The design provided an enhancement factor of 1.67x107 . Finally, Al nanoparticles with plasmonic resonance at UV wavelengths fabricated in between the Schottky contacts of an MSM detector on semi-insulating GaN was shown to yield 1.5 fold enhancement in absorption and photocurrent collection. Plasmonic enhancement in UV was studied for the first time with this study. Another UV-MSM photodetector on GaN that includes subwavelength apertures surrounded by nano-structured metal gratings was compared to a conventional design without gratings. Results indicated an 8 fold enhancement in the photocurrent at the resonant wavelength.en_US
dc.description.statementofresponsibilityCinel, Neval Aen_US
dc.format.extentxvi, 84 leaves, illustrations, graphsen_US
dc.language.isoEnglishen_US
dc.rightsinfo:eu-repo/semantics/openAccessen_US
dc.subjectplasmonicsen_US
dc.subjectsurface plasmon polaritonen_US
dc.subjectnano-particleen_US
dc.subjectlocalized surface plasmon resonanceen_US
dc.subjectSurface Enhanced Raman Spectroscopy (SERS)en_US
dc.subject.lccQC176.8.P55 C55 2013en_US
dc.subject.lcshPlasmons (Physics)en_US
dc.subject.lcshNanoparticles.en_US
dc.subject.lcshNanostructures--Optical properties.en_US
dc.subject.lcshSurface plasmon resonance.en_US
dc.subject.lcshBiosensors.en_US
dc.subject.lcshRaman spectroscopy.en_US
dc.subject.lcshPhotonics.en_US
dc.titleEBL fabricated plasmonic nanostructures for sensing applicationsen_US
dc.typeThesisen_US
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.publisherBilkent Universityen_US
dc.description.degreePh.D.en_US


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