In this study, DLC thin films were electrodeposited at low DC potential using a mixture of acetic acid and DI water with different ratio. The parameters of DLC thin film deposition include the DC potential, deposition temperature, concentration of electrolyte solution, were correlated to the growth mechanism. The amount of nitrogen incorporated into DLC thin films were varied with the deposited temperature. The characteristics of DLC films by various measurements such as : the I-t curves of DLC film growth, SEM, AFM, FTIR, XPS, Raman and N&K spectroscopy, were investigated in detail. Experimental results showed that the surface roughness decreased, and sp3/sp2+sp3 value of DLC increased with the deposition temperature and deposition time. Optical properties showed that the refractive index, optical energy gap increased with the deposition temperature. For SEM cross-section measurement, it showed that the thickness of DLC films decreased due to the erosion process. However, the N-DLC films become graphitization. According to our study, we find that the surface morphology of the N-DLC films are homogeneous and compact. However, with the increase of the deposition temperature, the ratio of sp3-C-N bonds increase and the ratio of sp2-C-C bonds decrease, and these lead to the increase of refractive index and optical energy gap.

In this thesis, two separate research topics are undertaken both in the general area of compact RF/microwave circuit design. The first topic involves characterizing the parasitic effects and error due to unused post-production tuning bars. Such tuning bars are used in microwave circuit designs to allow the impedance or length of a microstrip line to be adjusted after fabrication. In general, the tuning bars are simply patterns of small, isolated sections of conductor adjacent to the thru line. Changing the impedance or length of the thru line involves bonding the appropriate tuning bars to the line. Unneeded tuning bars are simply not removed and left isolated. Ideally, there should be no coupling between these unused tuning bars and the thru line. Therefore, the unused tuning bars should have a negligible effect on the circuit??s overall performance. To nullify the parasitic effects of the tuning bars, conventional wisdom suggests placing the bars 1.0 to 1.5 substrate heights away from the main line. While successful in the past, this practice may not result in the most efficient and cost-effective placement of tuning bars in today??s compact microwave circuits. This thesis facilitates the design of compact tuning bar configurations with minimum parasitic effects by analyzing the error attributable to various common tuning bar configurations with a range of parameters and offset distances. The error is primarily determined through electromagnetic simulations, and the accuracy of these simulations is verified by experimental results. The second topic in this thesis involves the design of compact microwave resonators using the transmission line approach to create negative refractive index metamaterials. A survey of the major developments and fundamental concepts related to negative refractive index technology (with focus on the transmission line approach) is given. Following is the design and measurement of the compact resonators. The resonators are also compared to their conventional counterparts to demonstrate both compactness and harmonic suppression.

New improved model was developed to calculate the absorption and refractive-index spectra in the band-edge region for all the important compound semiconductors. An accurate absorption model including Coulomb interaction and Urbach-broadened band edge has been demonstrated for direct bandgap semiconductors. We have developed a accurate model in which a piecewise linear approximation is used for the shape of the absorption spectrum. We also propose a steep-edged compound Lorentzian line-shape function (SCL-LSF) for modeling the Urbach tail, and the line broadening of exciton absorptions. The results of applying this fitting procedure to the absorption spectra of GaAs, InP and InAs are presented, and a consistent set of band parameters are extracted. The analytical absorption model is suitable for a complete closed-form Kramers-Kronig transform of the absorption spectrum to obtain the refractive index spectrum. A band-to-band Coulomb interaction model for the refractive index spectra is presented of AlxGa1-xAs for 0 < x < 0.412, and In0.53Ga0.47As ternary semiconductors at photon energies near and above the band gap. An accurate absorption model is used to calculate the contribution on the refractive index near band-edge region through a complete closed-form Kramers-Kronig transform. By including a single oscillator Sellmeier model for the high-energy absorption spectrum, closed-form expressions are obtained for the band-edge region refractive index. Both spectra are fully described in terms of a finite set of parameters that can be interpolated for all the important compound semiconductors. The refractive index spectra are extended beyond the band-gap energy and are in excellent agreement with the available experimental data. Our new model makes accurate modeling possible for devices such as electroabsorption and electrorefraction modulators.

No description available.

Two dimensional photonic crystal slabs are studied theoretically and experimentally for the application of refractive index sensing with a focus on increasing both quality factor and sensitivity simultaneously. An overview of simulation and experimental techniques, along with fabrication protocols used is given. Through the use of new wafer architectures which allow for an air substrate, sensitivity is enhanced in some cases by more than a factor of 2 from our previous studies. Combining this with a novel lattice proposed which greatly reduces fabrication tolerances, experimental quality factors above 10,500 are achieved while maintaining an experimental sensitivity of above 800 nm/RIU. The effects of a finite photonic crystal slab are studied through the group velocity of guided mode resonances, with an emphasis on zero-group velocity. Future applications of the designs proposed are discussed.

No description available.

Two dimensional photonic crystal slabs are studied theoretically and experimentally for the application of refractive index sensing with a focus on increasing both quality factor and sensitivity simultaneously. An overview of simulation and experimental techniques, along with fabrication protocols used is given. Through the use of new wafer architectures which allow for an air substrate, sensitivity is enhanced in some cases by more than a factor of 2 from our previous studies. Combining this with a novel lattice proposed which greatly reduces fabrication tolerances, experimental quality factors above 10,500 are achieved while maintaining an experimental sensitivity of above 800 nm/RIU. The effects of a finite photonic crystal slab are studied through the group velocity of guided mode resonances, with an emphasis on zero-group velocity. Future applications of the designs proposed are discussed.

No description available.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 85-93). Also available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.