Abstract The high-speed performance of the lump-type electroabsorption modulator (EAM) is mainly limited by RC-effect. By taking advantage of the distributive effects, the traveling-wave structure can overcome the RC-lump effect. However, in order to enhance the limitation imposed by the conventional slow-waveguide type of traveling-wave structure, the speed of the device is still mainly restricted by the distributed capacitance of the waveguide. In this work, a novel type of traveling-wave-electroabsorption-modulator based on the undercut-etching the active region is successfully fabricated and measured. The methods of the processing adopted here is to lower the capacitance by chemical-wet-etching and two-time subsequent undercut etching on active region to further decrease the parasitic capacitance between P-type and N-type cladding layer. Also, the optical scattering loss may be reduced due the smooth sidewall of the waveguide from the wet etching. The whole processing shown in this thesis includes the lift-off technique by lithography, the metalization for n-, p- contacts (by thermal evaporator) and CPW microwave transmission (by e-beam evaporator), and PMGI-planarization. ¡V15dB optical transmission, ¡V6dB electrical transmission loss and >20GHz 3dB bandwidth of electrical-to-optical response at 50£[termination is measured on this kind of devices. It exhibits a high potential on the application of high-speed optical-fiber link in the future.

In this thesis, we study high quality InN films grown on sapphire (0001) by plasma-assisted molecular beam epitaxy (PAMBE). We used double layers methods to reduce lattice mismatch successfully. In this experiment, we have two series of samples, about series of A use low temperature GaN (LT-GaN) as the buffer layer as compared with series of B use high temperature AlN (HT-AlN) as the buffer layer. By in situ reflection high-energy electron diffraction (RHEED), we got film¡¦s surface situation. Surface morphology of the samples was observed by atomic force microscope (AFM). By high resolution X-ray diffraction (HR-XRD) methods was analyzed quality and composition of InN films. Van der Pauw method (Hall) was used to determine carrier concentration and mobility. The optical properties of InN films under different growth conditions were investigated by photoluminescence (PL). By changing growth temperature of these samples, we found the series of A having some fine characters as the InN(0002) rocking curve was 343 arcsec and InN(10-12) rocking curve was nearly 1000 arcsec. The mobility and carrier density of these samples were approximately 1000 cm2/Vs and 3 x 1018 cm-3 by Van der Pauw method.

In this work, a novel type of optical waveguide, namely two-step undercut-etching Si waveguide (TSUESW), fabricated in Si-substrate is proposed and demonstrated. All this waveguide processing is based on two step of SF6-based dry etching method. In the first step, an anisotropic etching by Reactive Ion Etching (RIE) is used to define the waveguide core. After that, an undercut etching through an isotropic etching processing Electron Cyclotron Resonance (ECR) is then utilized to decouple the optical light of the waveguide core from Si substrate. In the measurement setup, an optical propagation loss coefficient of 2.89dB/cm is obtained by extracting from Fabry-Perot oscillation, suggesting the confined optical mode in TSUESW can be realized. A tapered optical waveguide is also designed and fabricated, where the core of tapered structure is defined as widths of from 20£gm to 6£gm for optical fiber coupler. A 4.13dB/cm of loss from 700£gm long waveguide is found in such tapered waveguide. Through the nonlinear properties of Si material, a Four-Wave Mixing (FWM) behavior is observed in tapered waveguide, further confirming the optical power can be highly confined in small core of TSUESW. It also should be noted that the waveguide technology template can be processed in a Si-substrate to realize CMOS-compatible processing, avoiding high-cost Silicon-On-Insulator (SOI) technology.

The vitality of the human figure has been an unending source of curiosity for artists from the beginning to now. Although many artists have focused their creativity to searching for the perfect, in fact, beautiful, human form, others have striven to convey the human experience within the spirit of their own era. The latter is true of this creative project, which has addressed the following problem: hog: could large-scale intaglio printmaking be used to 02arify the negative impact our rigid contemporary notion of beauty can have on individual women? The project was inspired by the work of Kaethe Kollwitz, German artist of the early 20th century whc used her technical drawing skills to translate her knowledge of war and famine shattered women into forceful lithographs and etchings. The insight she Portrayed vividly combined her intensely personal vision the Vicious events of her times: social commentary at its finest.The significance of the project has been, first of all, its benefit to myself, the artist. The journey which I undertook through historical research on Kollwitz; conceptual investigation of women and rigid norms for beauty; and extension of my technical expertise as an etcher-has produced insights about creating art that are invaluable to the mature artist. The second significance involves the viewer, whom I hope reconsiders the images of women displayed in contemporary society.The project’s five large-scale etchings of the female figure portray in a series my ideas about roles women are expected to assume in contemporary American society. These ideas unfolded especially during the creation of the first and second etchings.The report of the project deals extensively with the drawing and etching techniques used for each print; a description of each of the works; the ideas which inspired the content of the works; how these ideas were transformed into visual images; and the technical competencies that I acquired while working through each plate. / Department of Art

Highly fluid repellent have application in many industries ranging from marine to biomedical due to their self-cleaning antifouling properties. The development and implementation of these superhydrophobic (water contact angle >150 degrees ) and superoleophobic (oil contact angle > 150 degrees ) surfaces were studied in this thesis. We focused our studies on paper as a substrate for these superhydrophobic and superoleophobic surfaces. Cellulose based paper is a biodegradable, inexpensive material that is ideal for disposable use applications. Applying an oxygen plasma etching technique combined with the deposition of a fluoropolymer from a pentafluoroethane precursor, superhydrophobic paper can be attained. This superhydrophobic paper is functionalized by printing wax islands onto the surface, thereby creating areas of high fluid adhesion. These wax functionalized sheets are used to sample droplets from bulk droplets, with the sampled volume being controlled by the hysteresis of the wax island. Disposable biomedical devices can be envisioned from these wax designs. While these superhydrophobic surface excel at repelling water, they continue to readily absorb water. Formation of paper that is both superhydrophobic and superoleophobic, or superamphiphobic, is accomplished through a combination of steps: mechanical fiber refining, solvent exchange processing and plasma treatment. The fiber refining creates nano-scale fibrils that are separated in the solvent processing. Subsequent plasma treatment of oxygen etching and fluoropolymer deposition creates superamphiphobic paper, exhibiting contact angles of > 150 degrees for water, ethylene glycol, motor oil and n-hexadecane. Further studies were conducted to increase the strength of these superamphiphobic sheets by using layered paper. Development of superhydrophobic paper from a hydrophilic diamond-like carbon surface coating was also demonstrated. When combined with oxygen plasma etching, diamond-like carbon coated paper sheets attain superhydrophobic properties similar to fluoropolymer coated sheets. Based on the knowledge gained from the studies on paper, superhydrophobic surfaces are created on 304 and 316 stainless steels. Samples are etched in hydrofluoric acid and then passivated in nitric acid to create the necessary surface structure. Deposition of fluoropolymer onto the etched samples yields superhydrophobic properties.

Thesis (B.S.)--Rochester Institute of Technology, 1986. / Typescript. Includes bibliographical references (leaf 34).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 169-171). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--Rochester Institute of Technology, 1994. / Typescript. Includes bibliographical references (leaves 98-99).

Des efforts de miniaturisation sont nécessaires dans le domaine des dispositifs actifs implantables afin de limiter l’invasivité et de réduire les risques de complications suite aux opérations chirurgicales. Les marges de progression pour la réduction des dimensions tendent à se réduire pour les systèmes actuels tels que les stimulateurs cardiaques, les neurostimulateurs ou les capteurs autonomes in vivo. Une rupture technologique est nécessaire pour permettre de repousser les limites des systèmes actuels. Le titane est un matériau possédant des propriétés de biocompatibilité. Il est stable et inerte en contact avec les tissus humains. De plus, ses caractéristiques mécaniques en font un matériau prometteur pour le développement de microsystèmes implantables. Dans le cadre du projet R&D MISTIC (Micro-Structuration du Titane pour Innovations Cardiologiques), l’objectif principal de cette thèse est de développer une brique technologique sur la gravure profonde du titane pour l’intégration de microsystèmes dans des dispositifs actifs implantables. Des études concernant la gravure profonde du titane en plasma de Cl₂ ont été menées afin de déterminer les mécanismes mis en jeu. L’ajout d’espèces fluorées permet, par la création d’un nouveau chemin réactionnel, d’accroître la vitesse de gravure du titane et d’augmenter la sélectivité par rapport au masque de Nickel. Un procédé de gravure du titane sur une profondeur de 300 μm a été mis au point sur des plaquettes de 100 mm de diamètre. L’application des résultats de ces études et le transfert du procédé vers la gravure pleine plaque ont permis de réaliser des démonstrateurs de traversées électriques en titane. / Miniaturization efforts are required in the field of implantable active devices in order to limit invasiveness and reduce the risks of complications following surgical operations. Progression margins for the reduction of dimensions tend to be reduced for current systems such as cardiac pacemakers, neurostimulators or in vivo autonomous sensors. A technological break is needed to push the limits of current systems. Titanium is a material with biocompatibility properties. It is stable and inert in contact with the human tissues.Moreover, its mechanical characteristics make it a promising material for the development of implantable microsystems. As a part of the MISTIC R&D project (Micro-Structuring of Titanium for Innovations in Cardiology), the main objective of this PhD thesis is to develop a technological brick on the deep etching of titanium for the integration of microsystems in active implantable devices. Studies on the deep etching of titanium into Cl₂ plasma have been carried out in order to determine the mechanisms involved. Further, by adding fluorinated species in the process through the creation of a new reaction pathway, an increase in the titanium etch rate and an improvement of the selectivity with the nickel hard mask were achieved. A process for titanium etching over a depth of 300 μm has been developed on 100 mm diameter wafers. The application of the results of these studies and the transfer of the process to the full wafer etching made it possible to produce the demonstrators with titanium-based electrical feedthrough.

Silicon is an essential element in today’s modern world. Nanostructured Si is a more recently studied variant, which has currently garnered much attention. When its spatial dimensions are confined below a certain limit, its optical properties change dramatically. It transforms from an indirect bandgap material that does not absorb or emit light efficiently into one which can emit visible light at room temperatures. Although much work has been conducted in understanding the properties of nanostructured Si, in particular porous Si surfaces, a clear understanding of the origin of photoluminescence has not yet been produced. Typical synthesis approaches used to produce nanostructured Si, in particular porous Si and nanocrystalline Si have involved complex preparations used at high temperatures, pressures, or currents. The purpose of this thesis is to develop an easier synthesis approach to produce nanostructured Si as well as arrive at a clearer understanding of the origin of photoluminescence in these systems. We used a simple chemical etching technique followed by sonication to produce nanostructured Si suspensions. The etching process involved producing pores on the surface of a Si substrate in a solution containing hydrofluoric acid and an oxidant. Nanocrystalline Si as well as nanoscale amorphous porous Si suspensions were successfully synthesized using this process. We probed into the phase, composition, and origin of photoluminescence in these materials, through the use of several characterization techniques. TEM and SEM were used to determine morphology and phase. FT-IR and XPS were employed to study chemical compositions, and steady state and time resolved optical spectroscopy techniques were applied to resolve their photoluminescent properties. Our work has revealed that the type of oxidant utilized during etching had a significant impact on the final product. When using nitric acid as the oxidant, we formed nanocrystalline Si suspensions composed of particles with a crystal structure different than the common polymorph of Si. These particles emitted UV to blue wavelengths. Iron(III) chloride was also employed as an oxidant, and it created amorphous Si nanostructures from a bulk crystalline Si source. These suspensions showed ultra-bright visible photoluminescence, which could be tuned through engineering the surface.