High energy consumption is a crucial challenge in gas separation processes. With current energy intensive separation methods, there is a real need for more energy-efficient alternative technologies. Membrane technology demonstrates potential uses in industrial separation processes due to its potential energy efficiency, environmental friendliness, and small footprint. The continuous developments in material science contributed directly in enhancing the membrane performance through several engineering modifications such as thermal annealing, which presented visible improvements in gas permeation properties. The objective of this project was to investigate the thermal annealing of three fluorinated polymers (PAE1, PAE2, and TFMPD), aiming for favorable changes in gas permeation properties. In particular, each polymer was annealed for 3 h at various temperature values, targeting the intermediate stage, which is the zone where degradation started but a pure carbon structure stage was not formed yet. Overall, the thermal annealing study revealed that TFMPD had highest pure-gas separation performance among other polymers, in which the Robeson plots displayed that treated sample at 500 ºC surpassed the 2015 H2/CH4 upper bound, whereas the treated sample at 550 ºC surpassed 2019 upper bound of both CO2/CH4 and CO2/N2. Therefore, TFMPD can be a potential candidate polymer for membrane-based gas separation, especially for CO2 and H2 applications. This performance could be attributed to the internal structural changes in the polymer that occurred during thermal annealing. Hence, several characterization techniques were performed to detect these changes. For instance, it was realized that all polymers started crosslinking upon the thermal treatment at 350 ºC. Moreover, FTIR analysis indicated the release of several functional groups from treated polymers at high temperature values. Raman spectroscopy also confirmed that the observed substantial enhancement in gas permeation of annealed TFMPD at 550 ºC was due an early-stage carbon structure formation. Furthermore, several recommendations are proposed to continue the work in this project, which could lead to potential success of the thermally annealed polymers tested in this study in membrane-based gas separations applications.

A neutron flux on the order of 2·10²° neutrons/cm² at 0.18 MeV induces formation of point defects (vacancies and interstitials) in single crystal 3C-SiC causing a volume lattice expansion (swelling) of over 3% that can be measured by X-Ray diffraction. The crystal lattice can be completely restored with an annealing temperature equal to or higher than the irradiation temperature. This phenomenon serves as a basis for temperature measurements and allows the determination of the maximum temperature, if the exposure time is known. The single crystal 3C-SiC sensor is applicable to small, rotating and hard to access parts due to its size of 300-500 microns, wide temperature range of 100-1450 °C, "no-lead" installation, inert chemical properties and high accuracy of temperature measurements. These features make it possible to use the sensor in gas turbine blades, automotive engines, valves, pistons, space shuttle ceramic tiles, thermal protection system design, etc. This work describes the mechanism of neutron irradiation of single crystal 3C-SiC, the formation of point defects and their concentration, the different temperature measurement techniques, and the application of Maximum Temperature Crystal Sensors (MTCS) for maximum temperature measurements in both stationary and non-stationary regimes.

The phase transformation of anodized Ti film has been studied. Although X-ray diffraction detected only the amorphous TiO2 phase, transmission electron microscopy analysis showed that TiO nanocrystallites less than 10 nm in size were also present, which was further supported by x-ray photoelectron spectroscopy analysis. Anatase was found to appear gradually by annealing the as-anodized specimen in air at 500¡V550 oC, which was accompanied by a simultaneous disappearance of TiO nanocrystallites. In contrast, only rutile is formed by annealing the Ti film at the same temperatures. The results indicate that TiO can induce the formation of anatase, which is explained by the close similarity between their structures. (Chapter 1) Anatase phase of TiO2 has been shown to have very good biocompability. It was frequently observed on Ti surfaces after anodizing and thermal annealing treatments. In this report the mechanisms of the Ti to TiO and the TiO to anatase phase transitions in anodizing and annealing treatments of Ti have been studied by transmission electron microscopy. Ti thin films of two strong textures were first grown on the (001)NaCl substrates. In addition to amorphous TiO2, the anodization treatment caused the formation of TiO with an orientation relationship of (11-20)Ti // (220)TiO with Ti. The subsequent thermal annealing treatment caused the TiO to anatase transition with an orientation relationship of {200}TiO //{200}A. Pure anatase film was prepared by this method. (Chapter 2)

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L'utilisation des fibres SiC Tyranno SA3 (TSA3) et Hi Nicalon S (HNS) pour le renforcement de composites céramiques dédiées aux applications nucléaires impose l'étude de leur stabilité microstructurale et de leur comportement mécanique sous irradiation. La cinétique d'amorphisation des fibres a été étudiée et comparée à celle d'un matériau modèle, 6H-SiC monocristallin, sans que des différences significatives puissent être observées. La dose seuil d'amorphisation totale a été évaluée à ~0,4 dpa à température ambiante et aucune amorphisation complète n'a pas être obtenue pour des températures d'irradiation supérieures à 200 ºC. Les échantillons amorphes ont ensuite été recuits thermiquement ce qui a conduit, pour des températures élevées, à leur recristallisation mais également à une fissuration et une délamination de la zone irradiée. Ce processus d'endommagement était activé thermiquement avec une énergie d'activation de 1,05 eV. En ce qui concerne le comportement mécanique, le fluage d'irradiation des fibres TSA3 a été étudié en utilisant une machine de traction in situ implantée sur deux plateformes d'irradiation aux ions. On montre que sous irradiation ces fibres se déforment en fonction du temps avec des chargements thermique et mécanique où le fluage thermique est négligeable. Cette déformation est plus élevée pour les faibles températures d'irradiation en raison d'un couplage entre le gonflement et le fluage d'irradiation. Pour des températures voisines de 1000 ºC, le gonflement devient négligeable ce qui permet l'étude spécifique du fluage d'irradiation dont la vitesse de déformation présente une dépendance linéaire au flux d'ions. / The use of Tyranno SA3 (TSA3) and Hi Nicalon S (HNS) SiC fibers as reinforcement for ceramic composites for nuclear applications requires the characterization of its structural stability and mechanical behavior under irradiation. Ion-amorphization kinetics of these fibers have been studied and compared to the model material, i.e. 6H-SiC single crystals, with no significant differences. For all samples, full amorphization threshold dose yields ~0.4 dpa at room temperature and complete amorphization was not achieved for irradiation temperatures over 200 ºC. Successively, ion-amorphized samples have been thermally annealed. It is reported that thermal annealing at high temperatures not only induces the recrystallization of the ion-amorphized samples but also causes cracking and delamination. Cracking is reported to be a thermally driven phenomenon characterized by activation energy of 1.05 eV. Regarding the mechanical irradiation behavior, irradiation creep of TSA3 fibers has been investigated using a tensile device dedicated to in situ tests coupled to two different ion-irradiation lines. It is reported that ion-irradiation (12 MeV C4+ and 92 MeV Xe23+) induces a time-dependent strain under loads where thermal creep is negligible. In addition, irradiation strain is reported to be higher at low irradiation temperatures due to a coupling between irradiation swelling and irradiation creep. At temperatures near 1000 ºC, irradiation swelling is minimized hence allowing the characterization of the irradiation creep. Irradiation creep rate is characterized by a linear correlation between the ion flux and the strain rate and square root dependence with the applied load.

In recent years, non-fullerene acceptors (NFAs) have attracted enormous interest in the field of organic solar cells (OSCs), they improve power conversion efficiency (PCE) compared to the classical fullerene acceptor. In this work, OSCs based on PBDB-T as the donor material and the very well-known NFA ITIC, along with its fluorinated and chlorinated derivatives (IT-2F, IT-4F, IT-2Cl, IT-4Cl) were fabricated to investigate the effect of the halogenation end group on the photovoltaic parameters. Optical characterization reveals that both chlorination and fluorination are effective in downshifting the molecular energy levels and redshifting the absorption spectra, which results in higher Jsc but lower Voc compared to pristine ITIC. In addition, the halogenated ITIC device exhibited enhanced FF and PCE. Various optoelectronic techniques were also used to investigate the charge recombination dynamics and charge extraction process. It has been found that (IT-2F, IT-2Cl) show suppressed monomolecular recombination compared to di-substituted NFA (IT-4F, IT-4Cl). Furthermore, fluorinated ITIC has a longer charge carrier recombination lifetime but a lower carrier extraction rate. Lastly, the best-performing device from the preceding component mixtures PBDB-T:IT-2F was exposed to thermal annealing at different stages of the fabrication process to investigate how annealing affects the photovoltaic parameters. According to our findings, both post and 2-stage annealing improve FF and PCE, but the latter is even more beneficial. In further studies, the annealing effect on the HTL layer (MoOx) has also been investigated. Annealing improved the MoOx’s work function, resulting in higher internal electric field that thereby facilitated hole extraction, as demonstrated by TPC where 2-stage annealed devices exhibited a faster carrier extraction rate.

The ability to fabricate semiconductor wafers with spatially selected regions of different bandgap material is required for the fabrication of monolithic photonic integrated circuits (PIC's). Although this subject has been studied for three decades and many semiconductor engineering approaches have been proposed, the problem of achieving reproducible results has constantly challenged scientists and engineers. This concerns not only the techniques relaying on multiple sequential epitaxial growth and selective area epitaxy, but also the conventional quantum well intermixing (QWI) technique that has been investigated as a post-growth approach for bandgap engineering. Among different QWI techniques, those based on the use of different lasers appear to be attractive in the context of high-precision and the potential for cost-effective bandgap engineering. For instance, a tightly focused beam of the infrared (IR) laser could be used for the annealing of small regions of a semiconductor wafer comprising different quantum well (QW) or quantum dot (QD) microstructures. The precision of such an approach in delivering wafers with well defined regions of different bandgap material will depend on the ability to control the laser-induced temperature, dynamics of the heating-cooling process and the ability to take advantage of the bandgap engineering diagnostics. In the frame of this thesis, I have investigated IR laser-induced QWI processes in QW wafers comprising GaAs/A1GaAs and InP/InGaAsP microstructures and in InAs QD microstructures grown on InP substrates. For that purpose, I have designed and set up a 2-laser system for selective area rapid thermal annealing (Laser-RTA) of semiconductor wafers. The advantage of such an approach is that it allows carrying out annealing with heating-cooling rates unattainable with conventional RTA techniques, while a tightly focused beam of one of the IR lasers is used for `spot annealing'. These features have enabled me to introduce a new method for iterative bandgap engineering at selected areas (IBESA) of semiconductor wafers. The method proves the ability to deliver both GaAs and InP based QW/QD wafers with regions of different bandgap energy controlled to better than « 1nm of the spectral emission wavelength. The IBESA technique could be used for tuning the optical characteristics of particular regions of a QW wafer prepared for the fabrication of a PIC. Also, this approach has the potential for tuning the emission wavelength of individual QDs in wafers designed, e.g., for the fabrication of single photon emitters. In the 1st Chapter of the thesis, I provide a short review of the literature on QWI techniques and I introduce the Laser - RTA method. The 2nd Chapter is devoted to the description of the fundamental processes related to the absorption of laser light in semiconductors. I also discuss the results of the finite element method applied for modeling and semi-quantitative description of the Laser - RTA process. Details of the experimental setup and developed procedures are provided in the 3rd Chapter. The results concerning direct bandgap engineering and iterative bandgap engineering are discussed in the 4th and 5th Chapters, respectively.

De nos jours, les caméras sont de plus en plus utilisées lors de missions spatiales ou en centrale nucléaire pour des missions d'observations (civiles ou militaires) et de surveillance (vérification du déploiement de panneaux solaires, opérations extravéhiculaires, accident nucléaire, site de stockage). L'environnement spatial, les réacteurs civils nucléaires ou les lieux de stockage de déchets radioactifs sont des milieux radiatifs qui peuvent très fortement perturber les composants électroniques et les systèmes. Dans ces environnements, les rayonnements ionisants dégradent les paramètres électriques des composants électroniques. La dose totale ionisante conduit à l'apparition d'un nombre significatif de charges dans les oxydes des matériaux constituant les composants électroniques, modifiant leurs propriétés électriques. Il en résulte qu'une exposition à la dose totale ionisante peut entraîner une défaillance partielle ou totale d'un composant voire d'un système électronique embarqué.Dans le cadre de cette thèse, nous proposons une méthode de régénération pour guérir les paramètres électriques dégradés par la dose totale ionisante de composants électroniques soumis aux rayonnements ionisants. Cette méthode consiste à appliquer des cycles de recuit isothermes à un composant électronique. Dans un premier temps, cette méthode est appliquée sur des transistors MOS, et une étude est menée sur l'impact des différents paramètres clés du recuit (polarisation, température, durée de recuit, pas en dose entre chaque recuit). Dans un second temps, nous nous intéressons à des composants plus intégrés et plus récents tels que des capteurs d'images de type CMOS APS. Nous montrons expérimentalement l'impact d'un recuit sur ce type de composant et enfin, nous adaptons la méthode de régénération pour l'appliquer à ces capteurs APS afin d'augmenter leur durée de vie. / Nowadays, cameras are more and more used in space missions or nuclear plant for observation (civil or military) and monitoring missions (checking the deployment of solar panels, extravehicular operations, nuclear accident, and area storage). The space environment, nuclear reactors or radioactive waste storage areas are radiative environments that can greatly disturb electronic components and systems. In these environments, ionizing radiation degrades the electrical parameters of electronic components. The total ionizing dose induces significant charge build-up in oxides, degrading the electrical properties of the materials of electronic devices. That can result in the loss of functionality of the entire electronic system.In this thesis, we propose a regeneration method to recover the electrical parameters degraded by total ionizing dose of electronic components subjected to ionizing radiation. In this method isothermal annealing cycles are applied to electronic devices. In a first step, this method is applied on MOS transistors, and a study is conducted on the impact of various key parameters of annealing (bias, annealing temperature, annealing time, dose step between each annealing). In a second step, we focus on components more integrated and newer such as CMOS APS image sensors. We experiment what is the impact of annealing on this type of component and finally, the regeneration method is modified to be suitable on these APS sensors to increase their lifetime.

Electrical and structural properties of Bismuth thin films were studied simultaneously. Electrical properties of the Bismuth thin films have been characterized by measuring temperature dependent conductivity and Hall effect. Structural analysis were carried out by X-ray diffraction technique and using a room temperature Atomic Force Microscope (RT-AFM).

No description available.