Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Dennis G. Deppe. Vita. Includes bibliographical references. Also available from UMI.

Thesis (Ph. D.)--Physics, Georgia Institute of Technology, 2008. / Minqiang Li, Committee Member ; Constantine Yannouleas, Committee Member ; Michael Pustilnik, Committee Member ; Mei-Yin Chou, Committee Member ; Uzi Landman, Committee Member.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references and index.

Submitted by Gustavo Caixeta (gucaixeta@gmail.com) on 2017-02-16T10:41:56Z No. of bitstreams: 1 texto compĺeto.pdf: 927308 bytes, checksum: 87f5c56a4b88cc4b7ab4bed346550ec1 (MD5) / Made available in DSpace on 2017-02-16T10:41:56Z (GMT). No. of bitstreams: 1 texto compĺeto.pdf: 927308 bytes, checksum: 87f5c56a4b88cc4b7ab4bed346550ec1 (MD5) Previous issue date: 2003-12-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES, Brasil / Este trabalho faz uma breve revisão das técnicas de crescimento de cristais, tanto volumétricas, quanto em camadas. São abordadas as técnicas Czocrhalski, Bridgman, Epitaxia por Fase Líquida, por Fluxo Molecular e de Paredes Quentes. Esta última técnica é utilizada no crescimento de filmes de CdTe sobre substratos de Si. A caracterização das amostras produzidas é feita por microscopia de força atômica, técnica que é descrita em detalhes. Finalmente são apresentados os resultados do estudo sobre o processo de nucleação do CdTe sobre Si e discutida a possibilidade de utilização deste processo na fabricação de pontos quânticos auto-formados. / This work makes a brief revision of crystal growth techniques. It describes the techniques Czocrhalski and Bridgman, used for bulk crystal growth, and also Liquid Phase Epitaxy, Molecular Beam Epitaxy and Hot Wall Epitaxy, which are used for the growth of thin layers. The last technique (HWE) is used in the experimental part of this work for the growth of CdTe films on Si(111) substrates. The characterization of the produced samples is done by Atomic Force Microscopy. The results obtained about the nucleation process of CdTe on Si(111) are presented and the possibility of the use of this technique in the production of self-assembled quantum dots is discussed.

The development of a quantum computer presents one of the greatest challenges in science and engineering to date. The promise of more ecient computing based on entangled quantum states and the superposition principle has led to a worldwide explosion of interest in the elds of quantum information and computation. Decoherence is one of the main problems that gives rise to dierent errors in the quantum system. However, the discovery of quantum error correction and the establishment of the accuracy threshold theorem provide us comprehensive tools to build a quantum computer. This thesis contributes to this eort by investigating a particular class of quantum error correcting codes, called Decoherence free subsystems. The passive approach to error correction taken by these encodings provides an ecient means of protection for symmetrically coupled system-bath interactions. Here I will present methods for determining the subsystem-preserving evolutions for noiseless subsystem encodings and more importantly implementing a Universal quantum computing over three-quantum dots.

In this thesis, cadmium selenide (CdSe) quantum dots (QDs) are synthesized and characterized for patterning applications as well as for photovoltaic devices. The QDs were patterned and embedded into various polymers to form fluorescent composites. Their photophysical properties were investigated in detail. Through template assisted deposition the QDs-polymer composites were patterned into fluorescent nanorods. CdSe QDs were combined with multi-wall carbon nanotubes (CNTs) using a synthesized organic perylene derivative dye (N,N'-di(ethanethiol)-perylene-3,4,9,10-tetracarboxyl diimide) (ETPTCDI) as a link between QDs and CNTs. Upon testing, the QDs-ETPTCDI-CNTs nanocomposite displayed photoactive properties. Photophysical quenching studies of QD-ETPTCDI-CNTs provided better understanding of the electron-hole transfer of each component in the nanocomposite. The nanocomposite material was patterned onto microelectrode devices for photocurrent measurements under an AM1.5 solar simulated light source. These nanocomposites can be used as photovoltaic devices. The preliminary characterization studies of the device show excellent photoresponse under AM1.5 solar simulated light. The band gap alignment of each component of the nanocomposite and the charge transfer kinetics are the key to efficient electron-hole transfer. Optimization of the semiconducting material's interface can potentially make these nanocomposites a system for photovoltaic-based devices.

No description available.

Automated tracking of cells across timelapse microscopy image sequences typically employs complex segmentation routines and/or bio-staining of the tracking objective. Often accurate identification of a cell's morphology is not of interest and the accurate segmentation of cells in pursuit of non-morphological parameters is complex and time consuming. This thesis explores the potential of internalized quantum dot nanoparticles as alternative, bio- and photo-stable optical markers for tracking the motions of cells through time. CdTe/ZnS core-shell quantum dots act as nodes in moving light display networks within A549, epithelial, lung cancer cells over a 40 hour time period. These quantum dot fluorescence sources are identified and interpreted using simplistic algorithms to find consistent, non-subjective centroids that represent cell centre locations. The presented tracking protocols yield an approximate 91% success rate over 24 hours and 78% over the full 40 hours. The nanoparticle moving light displays also provide simultaneous collection of cell motility data, resolution of mitotic traversal dynamics and identification of familial relationships enabling the construction of multi-parameter lineage trees. This principle is then developed further through inclusion of 3 different coloured quantum dots to create cell specific colour barcodes and reduce the number of time points necessary to successfully track cells through time. The tracking software and identification of parameters without detailed morphological knowledge is also demonstrated through automated extraction of DOX accumulation profiles and Cobalt agglomeration accruement statistics from two separate toxicology assays without the need for cell segmentation.

Orientador: Carlos Lenz Cesar / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica / Made available in DSpace on 2018-08-04T09:35:25Z (GMT). No. of bitstreams: 1 Moreira_WendelLopes_M.pdf: 8515504 bytes, checksum: e80c0c01881efcfade7d7e39b55ade9a (MD5) Previous issue date: 2005 / Resumo: Não informado / Abstract: Not informed. / Mestrado / Física da Matéria Condensada / Mestre em Física