Aluminum- and gallium-bridged ansa-zirconocene compounds (Pytsi)Al[1]ZCP (31a) and (Pytsi)Ga[1]ZCP (31b) containing a bulky trisyl-based ligand with a pyridyl donor group [Pytsi = -C(SiMe3)2SiMe2(2-C5H4N)] were synthesized in 31% and 40% yield, respectively, by the reaction of (Pytsi)ECp2 [E = Al (29a), Ga (29b)] with Zr(NMe2)4 followed by reaction with Me3SiCl. Compounds 29a and 29b were prepared by the reaction of (Pytsi)ECl2 [E = Al (28a), E = Ga (28b)] with two equivalents of NaCp. The molecular structures of 29a and 29b were elucidated in solution by 1H and 13C NMR spectroscopy. Species 31a was characterized by multinuclear NMR spectroscopy while 31b was characterized by CHN elemental analysis, 1H and 13C NMR spectroscopy and mass spectrometry. Both species are the only known examples of aluminum- and gallium-bridged ansa-zirconocenes. Compound 31b in combination with MAO was applied and shown to be highly active for ethylene polymerization at room temperature. The activity of 31b was compared to that obtained for Cp2ZrCl2 using a glass reactor system and was found to be comparable. The influence of precatalyst concentration and ethylene pressure on activity of 31b was studied.

Aluminum- and gallium-bridged ansa-zirconocene compounds (Pytsi)Al[1]ZCP (31a) and (Pytsi)Ga[1]ZCP (31b) containing a bulky trisyl-based ligand with a pyridyl donor group [Pytsi = -C(SiMe3)2SiMe2(2-C5H4N)] were synthesized in 31% and 40% yield, respectively, by the reaction of (Pytsi)ECp2 [E = Al (29a), Ga (29b)] with Zr(NMe2)4 followed by reaction with Me3SiCl. Compounds 29a and 29b were prepared by the reaction of (Pytsi)ECl2 [E = Al (28a), E = Ga (28b)] with two equivalents of NaCp. The molecular structures of 29a and 29b were elucidated in solution by 1H and 13C NMR spectroscopy. Species 31a was characterized by multinuclear NMR spectroscopy while 31b was characterized by CHN elemental analysis, 1H and 13C NMR spectroscopy and mass spectrometry. Both species are the only known examples of aluminum- and gallium-bridged ansa-zirconocenes. Compound 31b in combination with MAO was applied and shown to be highly active for ethylene polymerization at room temperature. The activity of 31b was compared to that obtained for Cp2ZrCl2 using a glass reactor system and was found to be comparable. The influence of precatalyst concentration and ethylene pressure on activity of 31b was studied.

<p>Expanding the role of plasmonics in tomorrow's technology requires a broader knowledge base from which to develop such applications today. Several limitations to the current plasmonics field limit progress to incremental advances within a narrow set of materials and techniques rather than developing non-traditional metals and flexible growth and characterization methods. The work described herein will provide an introduction to the burgeoning field of spectroscopic ellipsometry for plasmonic characterization; in particular, the power of its real-time monitoring capabilities and flexibility will be demonstrated. More importantly, a novel plasmonic metal, gallium, is investigated in detail. Critical characteristics of gallium for an array of applications include its tunability over a wide spectral range, phase stability across a wide temperature range, plasmon stability even after air exposure, and an ultra high vacuum evaporation growth process enabling simple, alloyed nanostructure development. Deeper scientific investigation of the underlying ripening mechanisms driving gallium nanoparticle formation and in concert with in situ alloying paves the way for future work contributing to the development of advanced nanostructured alloys. Finally, this work demonstrates the first example of gallium nanoparticle-enhanced Raman spectroscopy - an area craving materials innovation. While the specific application of gallium for SERS detection is interesting, the far-reaching implication lies in the demonstrated potential for plasmonic gallium nanoparticles' ultimate use in a wider variety of applications enhanced by nanoscale materials.</p> / Dissertation

This work is to study the interface properties of Gallium-Gadolinium oxide / GaAs structures. The samples we probed were produced by depositing oxide films in situ on freshly grown n type GaAs (100) surface. Three different oxides were deposited : Ga2O3, Gd2O3, and (Ga2O3-Gd2O3) oxide mixture. Structural properties of the interfaces have been investigated by X-ray photoelectron spectroscopy (XPS). Using Ar+ sputtering to remove the oxide layer step by step, we are able to observe the depth profiles of these samples. No Asenic or Asenic oxides are observed at the interfaces of these samples. The Ga(3d) of Ga2O3 / GaAs interface shows three different oxidation states, whose binding energies are 21.5eV, 21.0eV and 20.3eV, respectively. The binding energy of O (1s) core level is about at 530eV. For (Ga2O3-Gd2O3) / GaAs, Ga(3d) peaks exhibit at 21.0eV and 20.3eV. Also, two O (1s) peaks were clearly observed: one is Ga-O at 532.2eV and the other is Gd-O at 530.1eV. For the Gd2O3 / GaAs, only one Ga(3d) peak shows at 20.3eV, and the O (1s) spectra exhibit two peaks related to Ga-O at 532eV and Gd-O at 530eV, similar to the data of (Ga2O3-Gd2O3) sample. In conclusion, the Ga2O3 / GaAs interface has a Ga2O3 and two non-fully oxidized GaxOy states (i.e. Ga+1, Ga+2). The (Ga2O3-Gd2O3) layer consists two non-fully oxidized GaxOy states. For the Gd2O3 / GaAs interface, the GaxOy (Ga+1) state is formed possibly by the competitive oxidation of Ga, which diffused from the GaAs substrate, with the Gd2O3.

Thesis (Ph. D.)--University of Oregon, 2000. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 122-126). Also available for download via the World Wide Web; free to University of Oregon users.

Originally presented as the author's thesis (Swiss Federal Institute of Technology), Diss. ETH No. 13547. / Summary in German and English. Includes bibliographical references.

Reproduction de : Thèse d'Etat : Sciences des matériaux : Toulouse, INPT : 1985. / Titre provenant de l'écran-titre. Bibliogr.130 réf.

Thèse de doctorat : Sciences et ingénierie des matériaux : Vandoeuvre-les-Nancy, INPL : 2005. / Titre provenant de l'écran-titre. Bibliogr.

Thèse de doctorat : Electronique : Lille 1 : 2000. / Bibliogr. en fin de chapitres.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references.