This work is focused on the visualization and thus in the aid in finding explanations for the behavior of polymer structures as they exist in solution. For this aim, preparation and imaging techniques based on cryo-TEM protocols were developed for a large variety of polymeric specimens using new commercially available devices and the results were compared with the findings of other means of structural investigations. The systems used in this work were chosen, as their investigations can be adapted to other polymer systems by slight adaptation of the preparation procedures.

The Lena West property near Lac des Bois, NT, held by Diamondex Resources Ltd., is an area of interest for exploration for kimberlitic features. In 2005, Frontier Geosciences Inc. was contracted to carry out seismic reflection and time-domain transient electromagnetic (TEM) surveys to investigate the possibility of kimberlite pipes being the cause of total magnetic intensity (TMI) anomalies previously identified on the property. One small part of the property, Area 1915, was surveyed with two perpendicular seismic reflection lines 1550 m and 1790 m long and three TEM lines consisting of six or seven individual soundings each with a 200 m transmitter loop. The results generated by Frontier Geosciences did not indicate any obvious vertical features that correlated with the TMI anomaly. The purpose of this study is to reprocess the seismic reflection data using different approaches than those of Frontier Geosciences and to invert the TEM data using a 1-D inversion code, EM1DTM recently developed by the UBC Geophysical Inversion Facility, to improve upon previous results and enhance the interpretation. A secondary objective is to test the robustness of EM1DTM when applied to observed TEM data, since prior to this study it had only been applied to synthetic data. Selective bandpass filtering, refraction and residual statics and f-x deconvolution procedures contributed to improved seismic images to the recorded two-way traveltime of 511.5 ms (approximately 1100 m depth). The TEM data were successfully inverted and converted to pseudo 2-D recovered resistivity sections that showed similar results to those from Frontier Geosciences. On the final seismic reflection sections, several strong reflectors are identified and the base of the overlying sedimentary layers is interpreted at a depth of ~600 m. The TEM results show consistent vertical structure with minimum horizontal variation across all lines to a valid depth of ~150 m. However, neither TEM nor seismic reflection results provide any information that correlates well with the observed TMI anomaly.

La méthode de levé géophysique à impulsion électromagnétique dans le domaine du temps (TDEM - Time-domain Electromagnetics) est couramment utilisée afin de détecter et caractériser la résistivité des couches du sol en fonction de la profondeur. Deux types de systèmes sont fréquemment utilisés dans le cadre de prospection et exploration minérale, soit les systèmes de surface et les systèmes aéroportés, ayant des caractéristiques et objectifs différents. Afin de caractériser les couches peu profondes et d’obtenir une résolution spatiale supérieure, il est préférable d’utiliser des systèmes de surface. Dans le cadre de cette thèse, un système émetteur – récepteur à géométrie fixe porté par deux opérateurs est développé et utilisé afin de déterminer les caractéristiques électriques de cibles naturelles et de cibles culturelles (dues à l’activité humaine). Ce système propose l’avantage d’avoir une résolution spatiale très élevée puisqu’il est opéré près du sol, cependant les vibrations et changements d'orientation causés par son déplacement créent des faibles déformations au niveau de la géométrie émetteur – récepteur qui influencent la qualité des données acquises. Il est possible de remédier à ce problème en modifiant la structure du système ou en caractérisant les vibrations à l’aide de capteurs supplémentaires installés sur la plateforme. Une méthode de traitement du signal numérique comportant un filtre adaptatif est décrite dans cette thèse et est utilisée afin de corriger les signaux lors de prises de mesures sur le terrain. Les recherches ont démontré qu’il est possible d’améliorer la qualité des données de levés avec la méthode de traitement numérique présentée. The time-domain electromagnetics (TDEM) geophysical survey method is frequently used in order to characterize the resistivity of the layers of the ground as a function of depth. In the case of mineral exploration and prospection, TDEM systems are most often operated either on the surface or airborne. Both methods have different characteristics and objectives. In order to characterize the subsurface layers and to have a high spatial resolution, it is better to use systems operated on the surface. In this thesis, a fixed geometry emitter – receiver system carried by two operators is developed and used in order to determine the electrical characteristics of natural targets and cultural targets (caused by human activity). This system has a very high spatial resolution since it is operated close to the ground, however, vibrations and changes in its orientation that are due to its operation create subtle deformations in the emitter – receiver geometry, which in turn influence the quality of the data acquired during the survey. It is possible to address this problem by modifying the structure of the supporting platform, or by characterizing the vibrations using different measuring instruments installed on the platform. A digital signal processing method using an adaptive filter is described in this thesis and is used in order to correct the signal acquired on a survey. The research has showed that it is possible to improve the survey data quality using the digital signal processing method presented.

UV and deep-UV emitters based on AlGaN/AlN heterostructures are very inefficient due to the high lattice mismatch of these films with sapphire substrates, leading to high dislocation densities. This thesis describes the characterisation of the nanostructures of a range of UV structures, including c-plane (polar) AlGaN epilayers grown on AlN template, and nonpolar GaN/AlGaN MQWs grown on a-plane GaN template. The results are based primarily on transmission electron microscopy (TEM), cathodoluminescence in the scanning electron microscope (SEM-CL), high-resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) measurements. The structural and optical properties of various types of defect were examined in the c-plane AlGaN epilayers. Strain analysis based on in-situ wafer curvature measurements was employed to describe the strain relief mechanisms for different AlGaN compositions and to correlate the strain to each type of defect observed in the epilayers. This is followed by the investigation of AlN template growth optimisation, based on the TMA pre-dose on sapphire method to enhance the quality and the surface morphology of the template further. The initial growth conditions were shown to be critical for the final AlN film morphology. A higher TMA pre-dose has been shown to enable a better Al coverage leading to a fully coalesced AlN film at 1 μm thickness. An atomically smooth surface of the template was achieved over a large 10 x 10 μm AFM scale. Finally, the investigation of UV emitters based on nonpolar crystal orientations is presented. The SiNx interlayer was able to reduce the threading dislocation density but was also found to generate voids with longer SiNx growth time. The relationship between voids, threading dislocations, inversion domain boundaries and their associated V-defects and the variation in MQW growth rate has been discussed in detail.

The Lena West property near Lac des Bois, NT, held by Diamondex Resources Ltd., is an area of interest for exploration for kimberlitic features. In 2005, Frontier Geosciences Inc. was contracted to carry out seismic reflection and time-domain transient electromagnetic (TEM) surveys to investigate the possibility of kimberlite pipes being the cause of total magnetic intensity (TMI) anomalies previously identified on the property. One small part of the property, Area 1915, was surveyed with two perpendicular seismic reflection lines 1550 m and 1790 m long and three TEM lines consisting of six or seven individual soundings each with a 200 m transmitter loop. The results generated by Frontier Geosciences did not indicate any obvious vertical features that correlated with the TMI anomaly. The purpose of this study is to reprocess the seismic reflection data using different approaches than those of Frontier Geosciences and to invert the TEM data using a 1-D inversion code, EM1DTM recently developed by the UBC Geophysical Inversion Facility, to improve upon previous results and enhance the interpretation. A secondary objective is to test the robustness of EM1DTM when applied to observed TEM data, since prior to this study it had only been applied to synthetic data. Selective bandpass filtering, refraction and residual statics and f-x deconvolution procedures contributed to improved seismic images to the recorded two-way traveltime of 511.5 ms (approximately 1100 m depth). The TEM data were successfully inverted and converted to pseudo 2-D recovered resistivity sections that showed similar results to those from Frontier Geosciences. On the final seismic reflection sections, several strong reflectors are identified and the base of the overlying sedimentary layers is interpreted at a depth of ~600 m. The TEM results show consistent vertical structure with minimum horizontal variation across all lines to a valid depth of ~150 m. However, neither TEM nor seismic reflection results provide any information that correlates well with the observed TMI anomaly. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

La méthode de levé géophysique à impulsion électromagnétique dans le domaine du temps (TDEM - Time-domain Electromagnetics) est couramment utilisée afin de détecter et caractériser la résistivité des couches du sol en fonction de la profondeur. Deux types de systèmes sont fréquemment utilisés dans le cadre de prospection et exploration minérale, soit les systèmes de surface et les systèmes aéroportés, ayant des caractéristiques et objectifs différents. Afin de caractériser les couches peu profondes et d’obtenir une résolution spatiale supérieure, il est préférable d’utiliser des systèmes de surface. Dans le cadre de cette thèse, un système émetteur – récepteur à géométrie fixe porté par deux opérateurs est développé et utilisé afin de déterminer les caractéristiques électriques de cibles naturelles et de cibles culturelles (dues à l’activité humaine). Ce système propose l’avantage d’avoir une résolution spatiale très élevée puisqu’il est opéré près du sol, cependant les vibrations et changements d'orientation causés par son déplacement créent des faibles déformations au niveau de la géométrie émetteur – récepteur qui influencent la qualité des données acquises. Il est possible de remédier à ce problème en modifiant la structure du système ou en caractérisant les vibrations à l’aide de capteurs supplémentaires installés sur la plateforme. Une méthode de traitement du signal numérique comportant un filtre adaptatif est décrite dans cette thèse et est utilisée afin de corriger les signaux lors de prises de mesures sur le terrain. Les recherches ont démontré qu’il est possible d’améliorer la qualité des données de levés avec la méthode de traitement numérique présentée. The time-domain electromagnetics (TDEM) geophysical survey method is frequently used in order to characterize the resistivity of the layers of the ground as a function of depth. In the case of mineral exploration and prospection, TDEM systems are most often operated either on the surface or airborne. Both methods have different characteristics and objectives. In order to characterize the subsurface layers and to have a high spatial resolution, it is better to use systems operated on the surface. In this thesis, a fixed geometry emitter – receiver system carried by two operators is developed and used in order to determine the electrical characteristics of natural targets and cultural targets (caused by human activity). This system has a very high spatial resolution since it is operated close to the ground, however, vibrations and changes in its orientation that are due to its operation create subtle deformations in the emitter – receiver geometry, which in turn influence the quality of the data acquired during the survey. It is possible to address this problem by modifying the structure of the supporting platform, or by characterizing the vibrations using different measuring instruments installed on the platform. A digital signal processing method using an adaptive filter is described in this thesis and is used in order to correct the signal acquired on a survey. The research has showed that it is possible to improve the survey data quality using the digital signal processing method presented.

Abstract: TEM is one of the most powerful technologies for material research. In-situ TEM is a TEM technique that allows us to study samples in real-time. Researchers can focus on one area and change the conditions under the electron beam to acquire much more data from the material than conventional TEM techniques. In this research, we use the in-situ TEM technique to observe the rechargeable aqueous zinc-ion batteries which have been considered as a promising candidate for next-generation batteries. We established the platform for the aqueous battery system and studied the charge and discharge processes for both cathode and anode materials in rechargeable aqueous zinc-ion batteries for the first time. Besides, we also combined low-dose TEM techniques to observe the HRTEM images of the electrode materials to probe the change on the surface of the cathode materials and the mechanism of dendrite growth in rechargeable aqueous zinc-ion batteries.

Afin d’optimiser les composants de l’industrie de la microélectronique, il est essentiel d’établir le lien entre la texture cristallographique des matériaux constitutifs et leurs propriétés électriques, thermiques et mécaniques. Ainsi, il est nécessaire de disposer d’outils capables de cartographier la morphologie et l’orientation cristallographique des grains à l’échelle nanométrique. La technique ACOM, implémentée sur un Microscope Electronique en Transmission (MET), permet d’obtenir ces informations en exploitant les figures de diffraction électronique. Dans cette thèse, les capacités de cette technique sont évaluées, à la fois pour déterminer la microtexture de matériaux confinés dans quelques dizaines de nanomètres, et pour répondre aux problématiques associées à la fabrication de nouveaux circuits. Cette étude montre dans un premier temps l’importance de l’optimisation des conditions opératoires du MET afin de diminuer les erreurs d’indexation. Des analyses quantitatives de microtexture sont ensuite menées sur des films minces de siliciures de nickel-platine pour différents dopage du substrat, concentration en platine, et température de recuit. Enfin, le cas d’une superposition de signaux de diffraction observé lorsque plusieurs grains sont contenus dans l’épaisseur de l’échantillon est étudié. Les résultats montrent que les erreurs d’indexation restent rares dans ce cas et que les grains de plus large fraction volumique sont majoritairement sélectionnés par l’algorithme d’indexation. Une méthode est alors proposée pour traiter la totalité de l’information détectée dans les clichés de diffraction. Elle s’appuie sur l’indexation successive des orientations cristallographiques après soustraction préalable des réflexions associées à l’orientation précédemment indexée. Les capacités de cet outil en termes de caractérisation de la morphologie des grains superposés sont finalement comparées à deux autres techniques basées sur la reconstruction d’images en champ sombre et sur la factorisation en matrices non-négatives. / The development of advanced nodes in microelectronics requires to understand the impact of crystal size and orientation on the electrical, thermal and mechanical properties of materials. New tools have been developed to map the grains orientation and morphology of nanometer-scaled structures. Among them, the Automated Crystal Orientation Mapping technique used on a Transmission Electron Microscope (ACOM-TEM) is based on the indexation of electron diffraction patterns. The aim of this study was to evaluate the abilities and limitations of the ACOM-TEM technique for the characterization of microelectronics-related materials. Consequently, its ability to analyze nano-sized materials and the possibility of answering problematics related to microelectronics front-end fabrication challenges were investigated. The study highlighted in the first place the importance of the TEM illumination settings. The results showed that minimizing the electron probe convergence angle even at the cost of a larger size has decreased mis-indexation issues. These optimum settings were used to perform quantitative texture analysis of NiPt-silicide thin films. Finally, the case of superimposed diffraction patterns related to overlapping grains was analyzed. Experiments showed that mis-indexing remains limited despite the superimposition and that grains with larger fraction volume were preferentially selected by template matching. A dedicated method was also proposed to overcome crystal overlapping issues. The approach is based on iterative re-indexation of diffraction patterns after subtraction of the reflections related to the previous ACOM best match. Considering the same diffraction patterns data-set, the capabilities of this method to recover the grains size and morphology were compared to two recent techniques based respectively on the analysis of virtual dark field (VDF) images and non-negative matrix factorization (NMF).

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