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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

New methodology for optical sensing and analysis

Bakker, Jimmy W. P. January 2004 (has links)
This thesis describes the research I have done, and partly will do, during my time as a PhD student in the laboratory of Applied Optics at Linköping University. Due to circumstances beyond the scope of this book, this incorporates three quite different projects. The first two, involving gas sensing and measuring on paper with ellipsometry, have been discontinued, whereas the third one, measuring fluorescence with a computer screen and web camera, is in full progress and will be until I complete my studies. Thus the purpose of this work also has several aspects. Partly, it describes performed research and its results, as well as theoretical background. On the other hand, it provides practical and theoretical background necessary for future work. While the three projects are truly quite different, each of them has certain things in common with each of the other. This is certainly also true for the necessary theory. Two of them involve spectroscopic ellipsometry, for example, while another pair needs knowledge of color theory, etc. This makes it impossible to separate the projects, despite of their differences. Hopefully, these links between the different projects, connecting the different chapters, will make this work whole and consistent in its own way. / <p>Report code: LiU-TEK-LIC-200 4-19. On the day of the public defence the status of article I was: In press and the status of article III was: Manuscript and has a new title. The old title was Computer screen photo-assisted spectroscopic fluorimetry.</p>
32

Optical characterization of high-[Kappa] dielectric structures

Price, James Martin, 1980- 23 August 2010 (has links)
Charge trapping dynamics in Si/SiO2/Hf(1-x)SixO2 and III-V film stack systems are characterized using spectroscopic ellipsometry (SE) and second harmonic generation (SHG). For the first time, discrete absorption features within the bandgap of the SiO2 interfacial layer are identified using SE, and their relation to both intrinsic and process-induced defects is proposed. Sensitivity of the absorption features to process conditions is demonstrated and evidence that these defects contribute to Vfb roll-off is presented. Defects in the Hf(1-x)SixO2 films are probed with fs laser-induced internal multi-photon photo-excitation (IMPE) and time dependent electrostatic field induced second harmonic (TD-EFISH) generation. For the as deposited HfO2 films, a unique TD-EFISH response is identified and explained by resonant two photon ionization of a specific point defect and subsequent tunneling of the photoelectrons to the Si substrate. Charge trapping kinetics for all Hf(1-x)SixO2 films are investigated. Two characteristic trap cross sections are identified and found to be insensitive to dielectric film and process conditions, and associated with a surface “harpooning” mechanism. EFISH from non-centrosymmetric III-V media, including GaAs and In0.53Ga0.47As, is also studied. The anisotropic and time dependent SHG response from different chemically treated In0.53Ga0.47As surfaces is clearly distinguishable and associated with a process-induced change in the surface depletion field. / text
33

Phase transitions in surfactant monolayers

Casson, Brian Derek January 1998 (has links)
No description available.
34

50%-50% Beam Splitters Using Transparent Substrates Coated by Single- or Double-Layer Quarter-Wave Thin Films

Sudradjat, Faisal 22 May 2006 (has links)
A pair of light beams that have orthogonal polarizations and equal intensity can be generated through reflection and refraction of a monochromatic light at a dielectric surface. Sytematic procedures to design beam splitters which can produce such output light beams are described in this thesis. Two designs that are of particular interest are prismatic substrates coated by a single layer and a double layer of thin films. Specific examples of each beam splitter in the visible and infrared are included. The performance of each beam splitter as a function of incidence angle, film thickness, and wavelength is also discussed.
35

Determination of Mueller matrix elements in the presence of imperfections in optical components

Chakraborty, Shibalik 15 May 2009 (has links)
The Polarizer-Sample-Analyzer (PSA) arrangement with the optical components P and A rotating with a fixed speed ratio (3:1) was originally introduced to determine nine Mueller matrix elements from Fourier analysis of the output signal of a photodetector. The arrangement is modified to the P'PSAA' arrangement where P' and A' represent fixed polarizers that are added at both ends with the speed ratio of the rotating components (P and A) remaining the same as before. After determination of the partial Mueller matrix in the ideal case, azimuthal offsets and imperfection parameters are introduced in the straight-through configuration and the imperfection parameters are determined from the Fourier coefficients. Finally, the sample is reintroduced and the full Mueller matrix elements are calculated to show the deviation from the ideal case and their dependency on the offsets and imperfection parameters.
36

Métrologie des dimensions critiques : scatterométrie et développements avancés / Metrology of critical dimension : scatterometry and advanced developments

Vauselle, Alexandre 19 December 2013 (has links)
L’industrie des nanotechnologies est un monde en constante évolution. Les améliorations dans les techniques de fabrication permettent de définir des composants de plus en plus petits. Afin de vérifier les dimensions fabriquées, la métrologie doit s’adapter et être capable de fournir des analyses basées sur des mesures optiques fiables et répétables. Ces travaux se focalisent dans un premier temps sur les procédés de fabrication des échantillons. Les techniques de dépôts, de photolithographies et de gravure sont présentées. Ces techniques nécessitent des outils de métrologie adaptés permettant un contrôle en ligne. Les équipements de métrologie disponibles sont donc présentés en se focalisant sur les techniques par imagerie comme la microscopie électronique à balayage ou transmission et les techniques par inversion telle que l’ellipsométrie et la scatterometrie. Le troisième chapitre est dédié aux applications de ces techniques en production. Les empilements étudiés sont généralement constitués de couches innovantes. La dernière partie est axée sur des méthodes de caractérisation de la rugosité par diffusion lumineuse sur des réseaux périodiques. / Nanotechnology industry is a world in constant evolution. Improvements in manufacturing techniques are used to define smaller and smaller components. To verify dimensions, metrology has to be improved to be able to provide reliable and repeatable analysis. This work focuses first on manufacturing process samples. Deposition techniques, photolithography and etching are introduced. These techniques require metrology tools adapted for in-line monitoring. Metrology equipments introduced in this thesis highlight the application of imaging techniques such as scanning electron microscopy or transmission and inversion techniques such as ellipsometry and scatterometry. The third chapter is dedicated to the application of these techniques to monitoring production. Thin films inspected are generally innovative layers. The last part is focused on methods for roughness characterization by light scattering on periodic gratings.
37

Desenvolvimento de um fotoelasticímetro e algumas aplicações. / Construction of a photoelasticimeter and some applications

Barboza, Ruy 15 June 1978 (has links)
Descreve-se detalhadamente a teoria e construção de um fotoelasticímetro, destinado ao estudo da estrutura de cristais iônicos deformados pela adição de impurezas. No método utilizado, a modificação do estado de polarização da luz pela amostra é investigada com o auxílio da modulação do feixe por uma placa fotoelástica. Exemplos de aplicação são apresentados. / The theory and construction of a photoelasticimeter are described in detail. The main use of the instrument will be in the study of the structure of ionic crystals deformed by the addition of impurities. In the employed method, the modification of the state of polarization of the light by the sample is investigated with the aid of a photoelastic board. Some examples of use are presented.
38

Spectroscopic ellipsometer for non-destructive characterization of semiconductors.

January 1993 (has links)
by Kwong-hon Lee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves [112-115]). / Chapter CHAPTER 1. --- INTRODUCTION / Chapter CHAPTER 2. --- PRINCIPLE OF ELLIPSOMETER / Chapter CHAPTER 3. --- MATHEMATICAL REPRESENTATION OF ELLIPSOMETRY / Chapter Section 3.1 --- Ambient Substrate / Chapter Section 3.2 --- Single Layer (Ambient-film substrate) / Chapter Section 3.3 --- Multilayer system (Isotropic Stratified planar structure) / Chapter CHAPTER 4. --- CLASSIFICATION OF ELLIPSOMETER / Chapter Section 4.1 --- Null-type Ellipsometer / Chapter Section 4.2 --- Photometric Ellipsometer / Chapter Section 4.3 --- Spectroscopic Ellipsometer / Chapter CHAPTER 5. --- CONSTRUCTION AND CALIBRATION OF THE SPECTROSCOPIC ELLIPSOMETER / Chapter Section 5.1 --- Design and construction / Chapter 5.1.1 --- Optical Assembly / Chapter 5.1.2 --- Electronic Circuit / Chapter 5.1.3 --- Micro-computer (Software) / Chapter 5.1.4 --- Modification of configuration / Chapter Section 5.2 --- Alignment and Calibration / Chapter 5.2.1 --- Alignment of Optical units / Chapter 5.2.2 --- Calibration of the system / Chapter 5.2.3 --- Measurements on standard samples / Chapter CHAPTER 6. --- ANALYSIS OF ELLIPSOMETRIC PARAMETERS / Chapter Section 6.1 --- Ambient-substrate model / Chapter Section 6.2 --- Ambient-layers model / Chapter 6.2.1 --- Parameter generator / Chapter 6.2.2 --- Least square fitting / Chapter 6.2.3 --- Choice of error function / Chapter CHAPTER 7. --- EXPERIMENTAL RESULT / Chapter Section 7.1 --- Spectra of Refractive index / Chapter 7.1.1 --- Low temperature MBE growth GaAs / Chapter 7.1.2 --- Amorphous Carbon / Chapter 7.1.3 --- High order x AlxGa1-xAs with different cooling rate / Chapter Section 7.2 --- Comparison of ellipsometric spectrum of SOI samples / Chapter 7.2.1 --- Difficulty in the analysis of multi-layer structure / Chapter 7.2.2 --- Silicon on insulator (SOI) / Chapter 7.2.2.1 --- The beam current effects / Chapter 7.2.2.2 --- Annealing after implantation / Chapter CHAPTER 8. --- CONCLUSION / Chapter Section8.1 --- Summary of the results / Chapter Section8.2 --- Suggestions for future work / REFERENCE / APPENDIX(A)MARQUART ALGORITHM / Chapter (B) --- CIRCUIT DIAGRAM
39

Swelling and protein adsorption characteristics of stimuli-responsive hydrogel gradients

Sterner, Olof January 2010 (has links)
<p>In this work, a gradient of interpenetrating polymer networks, consisting of anionic</p><p>and cationic polymers, has been investigated with respect to protein resistant</p><p>properties and swelling characteristics at different pH and ionic strength</p><p>conditions.</p><p> </p><p>The swelling and protein adsorption have been studied using <em>in situ </em>spectroscopic</p><p>ellipsometry(SE) and imaging surface plasmon resonance(iSPR) respectively.</p><p>It has been shown that, by altering the buffer pH, the region of lowest</p><p>protein adsorption on the surface could be moved laterally. The swelling has</p><p>similarly been shown to respond to both changes in pH and ionic strength. Additionally,</p><p>the arise of surface charge and the polymer swelling in solution, both a</p><p>consequence of the ionisation of fixed charges on the polymer, have been indicated</p><p>to occur at different buffer pH.</p><p> </p><p>The studied polymer systems show promising properties for future applications</p><p>in, for example, the biosensor area, where the surface chemistry can be</p><p>tailor-made to work optimally in a given environment.</p>
40

Interfacial Behaviour of Polyelectrolyte-Nanoparticle Systems

Sennerfors, Therese January 2002 (has links)
No description available.

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