Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Oregon, 2005. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 159-166). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Oregon Graduate Center, 1984.

No description available.

abstract: ABSTRACT Group III-nitride semiconductor materials have been commercially used in fabrication of light-emitting diodes (LEDs) and laser diodes (LDs) covering the spectral range from UV to visible and infrared, and exhibit unique properties suitable for modern optoelectronic applications. Great advances have recently happened in the research and development in high-power and high-efficiency blue-green-white LEDs, blue LDs and other optoelectronic applications. However, there are still many unsolved challenges with these materials. In this dissertation, several issues concerning structural, electronic and optical properties of III-nitrides have been investigated using a combination of transmission electron microscopy (TEM), electron holography (EH) and cathodoluminescence (CL) techniques. First, a trend of indium chemical inhomogeneity has been found as the indium composition increases for the InGaN epitaxial layers grown by hydride vapor phase epitaxy. Second, different mechanisms contributing to the strain relaxation have been studied for non-polar InGaN epitaxial layers grown on zinc oxide (ZnO) substrate. Third, various structural morphologies of non-polar InGaN epitaxial layers grown on free-standing GaN substrate have been investigated. Fourth, the effect of the growth temperature on the performance of GaN lattice-matched InAlN electron blocking layers has been studied. Finally, the electronic and optical properties of GaN nanowires containing a AlN/GaN superlattice structure have been investigated showing relatively small internal electric field and superlattice- and defect-related emissions along the nanowires. / Dissertation/Thesis / Ph.D. Physics 2011

Made available in DSpace on 2014-10-09T12:54:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:45Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:37:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:16Z (GMT). No. of bitstreams: 1 02037.pdf: 3257325 bytes, checksum: 6f7184b35c6dddcd40410864962f58fe (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:54:23Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:45Z (GMT). No. of bitstreams: 0 / A avaliação do desempenho dos detectores termoluminescentes de CaSO4:Dy, produzidos pelo IPEN, tem como objetivo apresentar uma alternativa aos dosímetros de LiF:Mg,Ti comerciais (TLD-100), amplamente empregados em radioterapia, na dosimetria de feixes clínicos de elétrons. Os dois tipos de detectores termoluminescentes foram caracterizados, com a utilização de objetos simuladores de PMMA, água sólida do tipo RMI-457 e água, em campos de radiação de elétrons de 4, 6, 9, 12 e 16 MeV de energias nominais, nos quais as curvas de dose-resposta foram obtidas e as doses superficial e profunda foram determinadas. A dependência da resposta termoluminescente com a energia nominal dos elétrons e com o objeto simulador empregado foram estudadas. O CaSO4:Dy apresentou o mesmo comportamento do LiF:Mg,Ti; de maneira que sua aplicação como uma alternativa às pastilhas TLD-100 na dosimetria de feixes de elétrons em radioterapia é viável e apresenta a sensibilidade à radiação de elétrons significativamente mais alta como principal vantagem. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:37:22Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:16Z (GMT). No. of bitstreams: 1 02037.pdf: 3257325 bytes, checksum: 6f7184b35c6dddcd40410864962f58fe (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP