A CHARACTERIZATION OF THE OXIDATION-REDUCTION CYCLE AND SURFACE MORPHOLOGY OF ELECTROCHEMICAL SURFACE ENHANCED RAMAN SCATTERING
AuthorTuschel, David Daniel, 1957-
Raman effect, Surface enhanced.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Degree ProgramGraduate College
Degree GrantorUniversity of Arizona
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Effects of orientation and mobility of surface modifiers on the selectivity and efficiency of chemical interactions at selected chemically modified surfaces.Burke, M.F.; Palmer, Christopher Paul.; Denton, M.B.; Pemberton, Jeanne E.; Barfield, M.; Vemulapalli, Krishna G. (The University of Arizona., 1991)Several surfaces chemically modified with a variety of surface modifiers have been studied using chromatographic, nuclear magnetic resonance, and computational techniques. The goal was to determine the effect of modifier structure on the solvation, selectivity, and efficiency of chemical interactions occurring at chemically modified surfaces. Oleyldimethylchlorosilane has been synthesized and bonded to silica to determine the effect of a conformational change at the center of the chain on the behavior of the entire surface. It has been shown with these studies that the configuration of the modifier plays an important role in determining the selectivity of chemical interactions at modified surfaces. By comparison with phospholipid bilayers, of the structure, solvation and dynamics of alkylmodified silicas has been achieved. Octyldimethylsilyl- and octadecyldimethylsilyl-modified silicas have been further reacted with t-butyltrichlorosilane, t-butyldimethylchlorosilane and trimethylchlorosilane to determine both the utility of t-butyltrichlorosilane as an end-capping reagent and the extent to which solvation of the near-surface region affects the performance of these surfaces. It was shown that the orientation and solvation of modifiers at the near surface has a profound effect on the selectivity and efficiency of chemical interactions at the surface. Sepharose gels modified with iminodiacetic acid have been studied by titrimetric and spectroscopic means. A model compound has been synthesized and characterized in solution. The results have led to a better understanding of the behavior of chelating agents at sepharose surfaces and the effects of immobilization on the behavior of ligands at a surface. Finally, quartz crystalline microbalances modified with physisorbed polymer layers have been studied by correspondence analysis. In this case, it has been shown that the polymer backbone of the modifying agent plays an important role in determining the selectivity of the modified surfaces. Together these studies have led to a more complete understanding of the effects of the structure and solvation of modified surfaces on the selectivity and efficiency of chemical interactions occurring at those surfaces. These observations apply to interactions occurring at chromatographic stationary phases and to interactions at chemically modified surfaces in general.
Surface Pretreatment for Thin Film Surface ReactivityThorsness, Adam G.; Muscat, Anthony; Muscat, Anthony; Sáez, A. Eduardo; Blowers, Paul (The University of Arizona., 2006)The formation of a self-limiting interface layer for the integration of high-k dielectric materials into silicon based transistor devices was investigated. Chlorine atoms were used to activate a liquid cleaned Si(100) surface for the reaction with H₂O(g). A saturation coverage of 0.8 monolayers of chlorine atoms was deposited on a hydrogen terminated Si(100) surface by exposure to Cl₂ gas at 10 Torr under ultraviolet illumination at 300 K. The self-limiting interface layer was formed by exposing the chlorine terminated surface to water vapor at P(HOH)=100 Torr and temperatures ranging from 325 to 373 K. The coverage of oxygen resulting from H₂O exposures was directly correlated with a decrease in the Cl coverage and ranged from 0.2-1.2 monolayers. Complete removal of surface chlorine was achieved by 100°C water exposures in 45 minutes. The final chapter summarizes three papers published which describe the moisture absorption into borophosphosilicate glass (BPSG) films and an investigation of a gas phase etching process applied to borosilicate glass (BSG), phosphosilicate glass (PSG), and BPSG films. The absorption and reaction of water with doped and undoped oxides as well as the effect of annealing was investigated using a variety of annealed BPSG films. Asdeposited (AD) and annealed (500, 750, and 900°C) borophosphosilicate glass (BPSG) films were characterized during aging, baking, and etching using transmission Fourier transform infrared spectroscopy and ellipsometry. The water content in the BPSG films increased steadily during storage at ambient conditions. The B-O bond was shown to be the primary site for water adsorption on the surface of the film. Water absorption into the film was consistent with a reaction-limited model. It is likely that the water present reacted readily with P=O groups forming P-O and PO-H. This slower reaction with P=O species is proposed as the rate-limiting step for water absorption. The etching of BPSG with gas phase HF produced a low volatility residue consisting of a mixture of boric acid B(OH)₃, phosphoric acid H₃PO₄, and water. Partial removal of the residue was accomplished using both direct and indirect UV–Cl₂ processes.