Thesis (M.S.)--University of Michigan, 2002. / Includes bibliographical references.

Thesis (doctoral)--Ludwig-Maximilians-Universität zu München, 1934.

Berlin, Freie Universiẗat, Diss., 2000. / Dateiformat: zip, Dateien im PDF-Format.

Berlin, Humboldt-University, Diss., 2004.

Universiẗat, Diss., 2005--Bonn.

Th. 3e cycle--Pharm.--Paris 5, 1980. N°: 10.

abstract: III-nitride alloys are wide band gap semiconductors with a broad range of applications in optoelectronic devices such as light emitting diodes and laser diodes. Indium gallium nitride light emitting diodes have been successfully produced over the past decade. But the progress of green emission light emitting devices has been limited by the incorporation of indium in the alloy, mainly due to phase separation. This difficulty could be addressed by studying the growth and thermodynamics of these alloys. Knowledge of thermodynamic phase stabilities and of pressure - temperature - composition phase diagrams is important for an understanding of the boundary conditions of a variety of growth techniques. In this dissertation a study of the phase separation of indium gallium nitride is conducted using a regular solution model of the ternary alloy system. Graphs of Gibbs free energy of mixing were produced for a range of temperatures. Binodal and spinodal decomposition curves show the stable and unstable regions of the alloy in equilibrium. The growth of gallium nitride and indium gallium nitride was attempted by the reaction of molten gallium - indium alloy with ammonia at atmospheric pressure. Characterization by X-ray diffraction, photoluminescence, and secondary electron microscopy show that the samples produced by this method contain only gallium nitride in the hexagonal phase. The instability of indium nitride at the temperatures required for activation of ammonia accounts for these results. The photoluminescence spectra show a correlation between the intensity of a broad green emission, related to native defects, and indium composition used in the molten alloy. A different growth method was used to grow two columnar-structured gallium nitride films using ammonium chloride and gallium as reactants and nitrogen and ammonia as carrier gasses. Investigation by X-ray diffraction and spatially-resolved cathodoluminescence shows the film grown at higher temperature to be primarily hexagonal with small quantities of cubic crystallites, while the one grown at lower temperature to be pure hexagonal. This was also confirmed by low temperature photoluminescence measurements. The results presented here show that cubic and hexagonal crystallites can coexist, with the cubic phase having a much sharper and stronger luminescence. Controlled growth of the cubic phase GaN crystallites can be of use for high efficiency light detecting and emitting devices. The ammonolysis of a precursor was used to grow InGaN powders with different indium composition. High purity hexagonal GaN and InN were obtained. XRD spectra showed complete phase separation for samples with x < 30%, with ~ 9% indium incorporation in the 30% sample. The presence of InGaN in this sample was confirmed by PL measurements, where luminescence from both GaN and InGaN band edge are observed. The growth of higher indium compositions samples proved to be difficult, with only the presence of InN in the sample. Nonetheless, by controlling parameters like temperature and time may lead to successful growth of this III-nitride alloy by this method. / Dissertation/Thesis / Ph.D. Physics 2011

Capture of the energy in sunlight relies mainly on the use of light-absorbing semiconductors, in solar cells and in water-splitting devices. While solar cell efficiency has increased dramatically since the first practical device was made in 1954, production costs for the most-efficient solar absorbers, III-V semiconductors, remain high. This is largely a result of use of expensive, slow growth methods which rely on hazardous gas-phase precursors. Alternative growth methods are necessary to lower the cost for III-V materials for use in solar cells and improve the practicality of water-splitting devices. The research goal of this dissertation is two-fold: to expand the capabilities of close-spaced vapor transport, an alternative growth method for III-Vs to demonstrate its compatibility with current technologies; and to explore the fundamental chemistry of close-spaced vapor transport as a growth method for these materials. This dissertation surveys plausibly lower-cost growth methods for III-V semiconductors (Chapter II) and presents in-depth studies on the growth chemistry of two ternary III-Vs: GaAs1-xPx (Chapter III) and Ga1-xInxP (Chapter IV). Finally, the growth of GaAs microstructures which could be utilized in a water-splitting device is studied (Chapter V). This dissertation includes previously published and unpublished co-authored material. / 2019-01-09

abstract: The structural validity of the WJ-III Cognitive was investigated using the GIA-Extended Battery test scores of 529, six-to-thirteen-year-old students referred for a psychoeducational evaluation. The results of an exploratory factor analysis revealed 11 of the 14 tests loaded on their expected factors. For the factors Gc, Gf, Gs, and Gv, both tests associated with the factor loaded highly; for Gsm, Glr, and Ga, only one test associated with each factor loaded highly. Obtained congruence coefficients supported the similarity between the factors Gs, Gf, Gc, Glr, and Gv for the current referred sample and the normative factor structure. Gsm and Ga were not found to be similar. The WJ-III Cognitive structure established in the normative sample was not fully replicated in this referred sample. The Schmid-Leiman orthogonalization procedure identified a higher-order factor structure with a second-order, general ability factor, g, which accounted for approximately 38.4% of common variance and 23.1% of total variance among the seven, first-order factors. However, g accounted for more variance in both associated tests for only the orthogonal first-order factor Gf. In contrast, the Gc and Gs factors accounted for more variance than the general factor for both of their respective tests. The Gsm, Glr, Ga, and Gv factors accounted for more variance than g for one of the two tests associated with each factor. The outcome indicates Gc, Gf, Gs, and Gv were supported and thus are likely factors that can be utilized in assessment while Gsm, Glr, and Gr were not supported by this study. Additionally, results indicate that interpretation of the WJ-III scores should not ignore the global ability factor. / Dissertation/Thesis / Ph.D. Educational Psychology 2012

Tesis para optar al grado de Magíster en Finanzas / El desempeño y la eficiencia del Sistema Bancario resultan ser de vital importancia para el desarrollo de un país, sobre todo ya que los Bancos muchas veces proveen el financiamiento de la producción de bienes de capital y consumo de una economía. Así, cubriendo las necesidades de los agentes económicos excedentarios y deficitarios de recursos monetarios, canalizan dichos flujos de efectivo hacia los sectores más productivos. Luego, a través de la banca, se lleva a cabo el proceso de intermediación que es el que facilita el flujo de dinero entre quienes desean invertir y no tienen suficientes recursos, y quienes poseen dinero y quieren rentabilizarlo. Esto se lleva a cabo gracias al pacto social imperante en el cual los Estados autorizan a los Bancos a emitir (colocar) dinero, toda vez que logren captar depósitos de algún agente del Mercado, lo que les permite lucrar ofreciendo seguros de liquidez al resto de la economía. Así los Bancos ganan el diferencial entre las tasas pagadas por los depósitos y las cobradas por los préstamos, más que compensando el riesgo de crédito. Sin embargo siempre existen descalces de plazos inherentes a los balances bancarios, lo que les hace Instituciones susceptibles a las corridas bancarias1 por parte de sus clientes, terminando muchas veces por colapsar en su operación. Dado su gran apalancamiento y tamaño, el rol de la Banca en el sistema de pagos de la economía hace que su fracaso sea lamentablemente muy costoso (costo sistémico). Por esta razón, estas instituciones muchas veces tienen acceso a la liquidez de los Bancos Centrales, y sus captaciones están sujetas a seguros de depósitos. De esta forma, se reduce en parte la probabilidad de fracaso no justificado, pero aumentando la rentabilidad privada de banqueros y accionistas al transferir cierto riesgo al Estado.