Lithium-ion batteries(LIBs) have dominated the energy storage market in the past two decades. The high specific energy, low self-discharge, relatively high power and low maintenance of LIBs enabled the revolution of electronic devices and electric vehicle industry, changed the communication and transportation styles of the modern world. Although the specific energy of LIBs has increased significantly since first commercialized in 1991, it has reached a bottleneck with current electrode materials. To meet the increasing market demand, it is necessary to develop high capacity electrode materials.<div><br></div><div>Current commercial anode material for LIB is graphite which has a specific capacity of 372 mAh g-1. Other group IV elements (silicon (Si), germanium (Ge), tin (Sn)) have much higher capacities. However, group IV elements have large volume change during lithiation/delithiation, leading to pulverization of active materials and disconnection between electrode particles and current collector, resulting in fast capacity fading. To address this issue, it is essential to understand the microstructural evolution of Si, Ge and Sn during cycling.<br></div><div><br></div><div>This dissertation is mainly focused on the morphological and structural evolution of Sn and Ge based materials. In this dissertation, anin situ focused ion beam-scanning electron microscopy (FIB-SEM) method is developed to investigate the microstructuralevolution of a single electrode particle and correlate with its electrochemical performance. This method is applied toall projects. The first project is to investigate the microstructural evolution of a Sn particle during cycling. Surface structures of Sn particles are monitored and correlated with different states of charge. The second project is to investigate the morphological evolution of Ge particles at different conditions. Different structures (nanopores, cracks, intact surface) appear at different cycling rates. The third project is to study selenium doped Ge (GeSe) anodes. GeSe and Ge particles are tested at the same condition. Se doping forms Li-Ge-Se network, provides fast Li transport and buffers volume change. The fourth project is to study the reaction front of Ge particle during lithiation. Micron-sized Ge particles have two reaction fronts and a wedge shape reaction interface, which is different from the well-known core-shell mode. The fifth project is to investigate antimony (Sb)-coated porous Ge particles. The Sb coating suppresses electrolyte decomposition and porous structure alleviates volume change. The results in this dissertation reveal fundamental information about the reaction mechanism of Sn and Ge anode. The results also show the effects of doping, porous structuring and surface coating of anode materials.</div>

In public opinion, protection against asteroids impact has always been on the agenda of space engineering. Actually it started from 1994 when Shoemaker Levy stroke Jupiter. This protection works in two steps: detection of threat and deflection. Some space agencies and foundations monitor the sky and set up scenario. Although the sky is nowadays well monitored and mapped, there is no global plan nowadays against this threat. This paper focuses on the deflection step, and aims at forecasting which variables are involved and their consequences on the deflection mission. In fact the result depends on several factors, like the time before hazardous moment, the accuracy of detection tools, the choice of deflection method, but the most unpredictable are human factors. This study shows a strategy and so tries to give some new response parts to the global deflection problem.

The assistance of thin film deposition with low-energy ion bombardment influences their final properties significantly. Especially, the application of so-called hyperthermal ions (energy <100 eV) is capable to modify the characteristics of the growing film without generating a large number of irradiation induced defects. The nitrogen ion beam assisted molecular beam epitaxy (ion energy <25 eV) is used to deposit GaN thin films on (0001)-oriented 6H-SiC substrates at 700 C. The films are studied in situ by reflection high energy electron diffraction, ex situ by X-ray diffraction, scanning tunnelling microscopy, and high-resolution transmission electron microscopy. It is demonstrated that the film growth mode can be controlled by varying the ion to atom ratio, where 2D films are characterized by a smooth topography, a high crystalline quality, low biaxial stress, and low defect density. Typical structural defects in the GaN thin films were identified as basal plane stacking faults, low-angle grain boundaries forming between w-GaN and z-GaN and twin boundaries. The misfit strain between the GaN thin films and substrates is relieved by the generation of edge dislocations in the first and second monolayers of GaN thin films and of misfit interfacial dislocations. It can be demonstrated that the low-energy nitrogen ion assisted molecular beam epitaxy is a technique to produce thin GaN films of high crystalline quality.

One conventional method for studying dislocations uses the Transmission Electron Microscope (TEM), a complex and expensive piece of equipment which requires extensive specimen preparation in order to thin the specimens to electron transparent thickness. Newer High Resolution Electron Backscatter Diffraction (HREBSD) methods of determining geometrically necessary dislocation content via cross-correlation promise to be able to produce estimates of the dislocation density of the sample over a larger area with considerably less preparation time and using a much more accessible instrument. However, the accuracy of the new EBSD technique needs more experimental verification, including consideration of possible changes in the specimen dislocation density due to the different preparation methods. By comparing EBSD and TEM dislocation measurements of Electron Transparent platinum specimens prepared using the Focused Ion Beam (FIB), along with EBSD dislocations measurements of specimens prepared by both FIB and mechanical polishing techniques, this paper seeks to verify the accuracy of the new method and identify any changes in the specimens’ apparent dislocation density caused by the different preparation processes.

No / A novel process chain for serial production of polymer-based devices incorporating both micro- and nano-scale features is proposed. The process chain is enabled by the use of Zr-based bulk metallic glasses (BMG) to achieve the necessary level of compatibility and complementarity between its component technologies. It integrates two different technologies, namely laser ablation and focused ion beam (FIB) milling for micro-structuring and sub-micron patterning, respectively, thus to fabricate inserts incorporating different length scale functional features. Two alternative laser sources, namely nano-second (NS) and pico-second (PS) lasers, were considered as potential candidates for the first step in this master-making process chain. The capabilities of the component technologies together with some issues associated with their integration were studied. To validate the replication performance of the produced masters, a Zr-based BMG insert was used to produce a small batch of micro-fluidic devices by micro-injection moulding. Furthermore, an experimental study was also carried out to determine whether it would be possible by NS laser ablation to structure the Zr-based BMG workpieces with a high surface integrity whilst retaining the BMG’s non-crystalline morphology. Collectively, it was demonstrated that the proposed process chain could be a viable fabrication route for mass production of polymer devices incorporating different length scale features.

In the electronics industry, several greenhouse gases (GHGs) are used as process gases in manufacturing processes. The organization RF360 as a Qualcomm Inc. subsidiary is using GHGs as input gases in the manufacturing processes dry etching, Chemical Vapor Deposition (CVD) and trimming in the fabrication plant in Munich.The estimation of GHG emissions from the use of process gases under Scope 1 requires a global and comprehensive approach to determine emission sources. This work provides the basis for the GHG emission estimation from process gas use under consideration of the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Dry etching and CVD process GHG emissions arecalculated using the Tier 2c method with process specific default emission factors. The process GHG emissions from trimming are characterized under Tier 3a, by determination of site-specific process emission factors. These emission factors are obtained from FTIR measurements in the inline. The measurement results show the input gas NF3 is largely not converted or destroyed in the trimming process. The total GHG emissions resulting from process gas use in the considered processes are determined by emissions of NF3, CF4 and N2O. The implementation and improvement of the approach requires further measurements of site-specific emission factors in the processes and Destruction Removal Efficiencies of the abatement systems.

This thesis aims to measure the mechanical properties of ceramics on the microscale using microcantilever beams. Focussed Ion Beam milled triangular cross-sectional beams (approximately 3 x 5 x 20µm) were fractured using a nanoindenter to measure the Young’s modulus, fracture strength, and fracture toughness. By developing the technique with a sapphire bicrystal, it was found that the mechanical properties could be successfully ascertained if correction factors were used. Experiments and theoretical work showed that sapphire and polycrystalline alumina beams undergo moisture assisted sub-critical crack growth when tested in air. Whilst corrections for the Young’s modulus have been previously reported, this is the first reported attempt to correct for the notch tip residual stress and the first to consider sub-critical crack growth. Once these factors were characterised using the sapphire bicrystal, the technique was applied to a range of different ceramics, such as polycrystalline α-alumina and silicon nitride. These are the first reported direct measurements the grain boundary toughness of these ceramics using microcantilever beams. The grain boundary toughness was correlated with the macroscopic fracture properties and the characteristics of the ceramic (grain boundary composition, impurities, and fracture mode). Two grades of α-alumina were used and the macro- and micro-scale properties extensively compared. The damage evolution during uniaxial compression of alumina was investigated in depth, and compared to a previous reported microcrack evolution model using the measured grain boundary toughness. Investigation of whether deformation twins formed during loading was undertaken and the phenomenon was shown to not occur.

Ion beam therapy is an innovative radiotherapy technique using mainly carbon ion and proton irradiations. Its aim is to improve the current treatment modalities. Because of the sharpness of the dose distributions, a control of the dose if possible in real time is highly desirable. A possibility is to detect the prompt gamma rays emitted subsequently to the nuclear fragmentations occurring during the treatment of the patient. In a first time two different Compton cameras (double and single scattering) have been optimised by means of Monte Carlo simulations. The response of the camera to a photon point source with a realistic energy spectrum was studied. Then, the response of the camera to the irradiation of a water phantom by a proton beam was simulated. It was first compared with measurement performed with small-size detectors. Then, using the previous measurements, we evaluated the counting rates expected in clinical conditions. In the current set-up of the camera, these counting rates are pretty high. Pile up and random coincidences will be problematic. Finally we demonstrate that the detection system is capable to detect a longitudinal shift in the Bragg peak of +or- 5 mm, even with the current reconstruction algorithm.

PIXE, Particle Induced X-ray Emission, est une méthode d’analyse multiélémentaire, rapide, non destructive, basée sur la détection des rayons X caractéristiques émis suite à l’interaction de particules chargées avec la matière. Cette méthode est usuellement utilisée avec des protons accélérés à une énergie de l’ordre de quelques MeV dans des domaines d’applications variés, atteignant une limite de détection de l’ordre de quelques μg/g (ppm). Cependant, la profondeur d’analyse est relativement limitée. Grâce au cyclotron ARRONAX, nous pouvons utiliser des protons ou des particules alpha jusqu’à une énergie de 70 MeV pour mettre en œuvre la technique PIXE à haute énergie. Avec de telles énergies, nous excitons préférentiellement les raies X K, plus énergétiques que les raies L utilisées dans la PIXE classique pour l’analyse des éléments lourds. L’analyse d’échantillons épais, en profondeur, est ainsi accessible. Pour l’analyse des éléments légers, nous pouvons utiliser la détection de rayons gamma émis pas les noyaux excités en combinant les méthodes PIGE et PIXE. Nous allons tout d’abord présenter les caractéristiques et les principes d’analyse de la méthode PIXE à haute énergie que nous avons développée à ARRONAX. Nous détaillerons ensuite les performances atteintes, notamment en termes de limite de détection dans différentes conditions expérimentales. Enfin, nous présenterons les résultats obtenus pour l’analyse d’échantillons multicouches et la quantification d’éléments traces dans des échantillons épais. / Particle Induced X-ray Emission (PIXE) is a fast, nondestructive, multi-elemental analysis technique. It is based on the detection of characteristic X-rays due to the interaction of accelerated charged particles with matter. This method is successfully used in various application fields using low energy protons (energies around few MeV), reaching a limit of detection of the order the μg/g (ppm). At this low energy, the depth of analysis is limited. At the ARRONAX cyclotron, protons and alpha particles are delivered with energy up to 70 MeV, allowing the development of the High Energy PIXE technique. Thanks to these beams, we mainly produce KX-rays, more energetic than the LX-rays used with standard PIXE for the heavy elements analysis. Thus, in depth analysis in thick materials is achievable. For light element analysis, the PIGE technique, based on the detection of gamma rays emitted by excited nuclei, may be used in combination with PIXE. First of all, we will introduce the characteristics and principles of high energy PIXE analysis that we have developed at ARRONAX. Then we will detail the performance achieved, particularly in terms of detection limit in various experimental conditions. Finally, we present the results obtained for the analysis of multilayer samples and quantification of trace elements in thick samples.

Cette thèse porte sur l'étude de la production d'une source d'ionsCes travaux de thèse ont consisté à étudier la faisabilité d'une source d'ions césium brillante et de faible dispersion énergétique à partir d'atomes froids dans le but de la coupler à une optique de faisceau d'ions focalisés (FIB).Il s'agit de produire une source ionique continue, de fort courant et de plus faible dispersion en énergie que les sources actuellement utilisées. Un schéma expérimental innovant a donc été imaginé.Un flux continu d'atomes de césium est issu d'un four à recirculation. Les atomes sont ensuite collimatés et compressés en se basant su les techniques de refroidissement d'atomes par laser. Des simulations de la mélasse optique pour la collimation et du MOT-2D pour la compression sont présentées. Issus d'un jet effusif de césium produit par un four à recirculation, la collimation grâce à une mélasse optique et la compression effectuée en en utilisant un MOT-2D des atomes de césium a été étudiée. Le schéma d'ionisation des atomes de césium passe par une excitation vers un état de Rydberg puis par une ionisation par champ électrique. Les propriétés remarquables des atomes pour ces niveaux d'énergie permettent d'obtenir une ionisation des atomes en champ électrique quasi-instantanée qui permet la minimisation de la dispersion énergétique. Nous avons développer une simulation permettant d'étudier les propriétés du champ électrique nécessaire pour l'ionisation afin de choisir le niveau de Rydberg approprié. Des simulations complémentaires ont permis de définir et de concevoir les électrodes nécessaires à la production du champ électrique d'excitation et d'ionisation. Une première étude des effets coulombiens de la source d'ions lors de l'ionisation des atomes de Rydberg est présentée. Enfin, l'étude théorique du couplage de la source obtenue avec une optique de faisceaux d'ions focalisés est réalisée.Un montage expérimental vient compléter ces diverses études et a permis d'obtenir les premiers résultats. / The main goal of this thesis consists on studying the production of a bright ion cesium source with a low energy dispersion. In this work, the technology of cold atoms is used to coupled this source with optical elements of focused ion beams (FIB).A cw ionic source with high current and small energy spread is necessary to complete the performances of others available sources. A new experimenal scheme is presented here.A continuous high flux of cesium atoms is produced by a recirculating oven. The atoms are the collimated and compessed using laser cooling technology. Several simulations concerning the collimation and the compression have been made.A different way of producing ions comes from the excitation in an electric field of Rydberg atoms and then their ionization in an electric field. The remarkable properties of Rydberg atoms show the possibilty to ionize them almost instantanely reducing this way the energy spread. In the work several simulations indicate the way to choose the right Rydberg state for this application and the correct corresponding electric field.Further simulations determinate the electrdes needed for the excitation and the ionization of the Rydberg atoms from the beam. Moreover, a first study of the coulombian effects occuring in this ion source is described. Finally, a theorical study of the ion source and optic FIB coupling is shown.The description of the experimental setup and the first results complete this work.