Dissertations / Theses on the topic 'HRTEM'
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Geipel, Thomas. "Applications of HRTEM in materials science problems and dislocation simulations." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1057163293.
Full textDickinson, Calum. "Metal oxide porous single crystals and other nanomaterials : an HRTEM study." Thesis, University of St Andrews, 2007. http://hdl.handle.net/10023/217.
Full textSenapati, Sephalika. "Evolution of Lamellar Structures in AL-AG Alloys." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3067.
Full textM.S.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
Saito, Mitsuhiro. "HRTEM investigations of structure and composition of polar Pd/ZnO heterophase interfaces." Stuttgart Max-Planck-Inst. für Metallforschung, 2005. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-25889.
Full textІстратов, М. Є. "TEM–HRTEM дослідження структури наноламінатних (Al0.5Ti0.5)N/ZrN покриттів та перспективи застосування у біомедичній галузі." Master's thesis, Сумський державний університет, 2020. https://essuir.sumdu.edu.ua/handle/123456789/81695.
Full textMuga, Ibarra Francisco Javier. "Comportamiento Mecánico y Microestructural de una Aleación Cu-1,8%p.Al-0,5%p.Be en el Rango Post-Superelástico." Tesis, Universidad de Chile, 2008. http://repositorio.uchile.cl/handle/2250/103146.
Full textKurasch, Simon [Verfasser]. "Atom-by-atom observations on defect formation and dynamics in 2D materials studied by HRTEM / Simon Kurasch." Ulm : Universität Ulm. Fakultät für Naturwissenschaften, 2014. http://d-nb.info/1046623370/34.
Full textChen, Qu. "Structural studies of defects in two-dimensional materials with atomic resolution." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:392f2b1d-0488-4d10-96d9-817def04db2a.
Full textMa, Yanhang. "Structural study of nano-structured materials: electron crystallography approaches." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-129233.
Full textCeballos, Sanchez Oscar. "Stabilité thermique de structures de type TiN/ZrO2/InGaAs." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAY027/document.
Full textIII-V compound semiconductors, in particular InGaAs, are considered attractivealternative channel materials to replace Si in complementary metal-oxidesemiconductor(MOS) devices. Its high mobility and tunable band gap, requirementsfor high performance device design, have placed InGaAs as a promising candidate.However, the interfacial thermal stability and chemistry of high-k dielectrics on InGaAsis far more complex than those on Si. While most studies are focused on variouspassivation methods, such as the growth of interfacial passivation layers (Si, Ge, andSi/Ge) and/or chemical treatments to improve the quality of high-k/InGaAs interface,phenomena such as the out-diffusion of atomic species from the substrate as aconsequence of the thermal treatments have not been carefully studied. The thermaltreatments, which are related with integration processes of source and drain (S/D),lead to structural changes that degrade the electrical performance of the MOS device.A proper characterization of the structural alterations associated with the out-diffusionof elements from the substrate is important for understanding failure mechanisms. Inthis work it is presented an analysis of the structure and thermal stability ofTiN/ZrO2/InGaAs stacks by angle-resolved x-ray photoelectron spectroscopy (ARXPS).Through a non-destructive analysis method, it was possible to observe subtle effectssuch as the diffusion of substrate atomic species through the dielectric layer as aconsequence of thermal annealing. The knowledge of the film structure allowed forassessing the In and Ga depth profiles by means of the scenarios-method. For the asdeposited sample, In-O and Ga-O are located at the oxide-semiconductor interface. Byassuming different scenarios for their distribution, it was quantitatively shown thatannealing causes the diffusion of In and Ga up to the TiO2 layer. For the sampleannealed at 500 °C, only the diffusion of indium was clearly observed, while for thesample annealed at 700 °C the diffusion of both In and Ga to the TiO2 layer wasevident. The quantitative analysis showed smaller diffusion of gallium (~ 0.12 ML) thanof indium (~ 0.26 ML) at 700 °C/10 s. Since the quantification was done at differenttemperatures, it was possible to obtain an approximate value of the activation energyfor the diffusion of indium through zirconia. The value resulted to be very similar topreviously reported values for indium diffusion through alumina and through hafnia.~ vi ~Complementary techniques as high resolution transmission electron microscopy (HRTEM),energy dispersive x-ray spectroscopy (EDX) and time of flight secondary ion massspectrometry (TOF-SIMS) were used to complement the results obtained with ARXPS.Specially, TOF-SIMS highlighted the phenomenon of diffusion of the substrate atomicspecies to the surface
Compuestos semiconductores III-V, en particular InxGa1-xAs, son consideradosmateriales atractivos para reemplazar el silicio en estructuras metal-oxidosemiconductor(MOS). Su alta movilidad y flexible ancho de banda, requisitos para eldiseño de dispositivos de alto rendimiento, han colocado al InxGa1-xAs como uncandidato prometedor. Sin embargo, la estabilidad térmica en la interfazdieléctrico/InxGa1-xAs es mucho más compleja que aquella formada en la estructuraSiO2/Si. Mientras que la mayoría de los estudios se centran en diversos métodos depasivación tales como el crecimiento de las capas intermedias (Si, Ge y Si/Ge) y/otratamientos químicos para mejorar la calidad de la interfaz, fenómenos como ladifusión de las especies atómicas del sustrato como consecuencia del recocido no hansido cuidadosamente estudiados. Los tratamientos térmicos, los cuales estánrelacionados con los procesos de integración de la fuente y el drenador (S/D) en undispositivo MOSFET, conducen a cambios estructurales que degradan el rendimientoeléctrico de un dispositivo MOS. Una caracterización apropiada de las alteracionesestructurales asociadas con la difusión de los elementos del substrato hacia las capassuperiores es importante para entender cuáles son los mecanismos de falla en undispositivo MOS. En este trabajo se presenta un análisis de la estructura y laestabilidad térmica de la estructura TiN/ZrO2/InGaAs por la espectroscopía defotoelectrones por rayos X con resolución angular (ARXPS). A través de un método deanálisis no destructivo, fue posible observar efectos sutiles tales como la difusión delas especies atómicas del sustrato a través del dieléctrico como consecuencia delrecocido. El conocimiento detallado de la estructura permitió evaluar los perfiles deprofundidad para las componentes de In-O y Ga-O por medio del método deescenarios. Para la muestra en estado como se depositó, las componentes de In-O yGa-O fueron localizadas en la interfaz óxido-semiconductor. Después del recocido, semuestra cuantitativamente que éste causa la difusión de átomos de In y Ga hacia a lascapas superiores. Asumiendo diferentes escenarios para su distribución, se muestraque el recocido provoca la difusión de In y Ga hasta la capa de TiO2. Para la muestrarecocida a 500 °C, se observó claramente la difusión de indio, mientras que para lamuestra recocida a 700 °C tanto In y Ga difunden a la capa de TiO2. El análisis~ iv ~cuantitativo mostró que existe menor difusión de átomos de galio (0.12 ML) que deindio (0.26 ML) a 700 °C/10 s. Puesto que el análisis sobre la cantidad de materialdifundido se realizó a diferentes temperaturas, fue posible obtener un valoraproximado para la energía de activación del indio a través del ZrO2. El valor resultóser muy similar a los valores reportados previamente para la difusión de indio a travésde Al2O3 y a través de HfO2. Con el fin de correlacionar los resultados obtenidos porARXPS, se emplearon técnicas complementarias como la microscopía electrónica detransmisión (TEM), la espectroscopía de energía dispersiva (EDX) y la espectrometríade masas de iones secundarios por tiempo de vuelo (SIMS-TOF). Particularmente, TOFSIMSdestacó el fenómeno de difusión de las especies atómicas sustrato hacia lasuperficie
Duncan, Laura Kristin. "Characterization of C60 Nanoparticles in Aqueous Systems." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/32439.
Full textMaster of Science
Prestat, Eric. "Étude quantitative TEM et STEM du mûrissement de nanoparticules de Pt et de semi-conducteur ferromagnétique Ge(Mn)." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00998250.
Full textSaito, Mitsuhiro [Verfasser]. "HRTEM investigations of structure and composition of polar Pd/ZnO heterophase interfaces / Max-Planck-Institut für Metallforschung, Stuttgart. Vorgelegt von Mitsuhiro Saito." Stuttgart : Max-Planck-Inst. für Metallforschung, 2006. http://d-nb.info/980323622/34.
Full textAdora, Sébastien. "Analyse XAS, XRD et HRTEM des étapes délaboration des nanoparticules de platine réalisées sur carbone activé par imprégnation de H2PtCl6 puis réduction électrochimique." Grenoble INPG, 2002. http://www.theses.fr/2002INPG0163.
Full textFalke, Meiken. "Elektronenmikroskopische Untersuchung der Bildung von CoSi$_{2}$-Schichten auf Si(001)." Doctoral thesis, Universitätsbibliothek Chemnitz, 1999. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199900532.
Full textThe formation of CoSi$_{2}$ by solid phase reaction using different methods is analysed by means of electron microscopy. The results correspond to RBS and XRD measurements. A description of the sample preparation for transmission electron microscopy is given. The formed silicide films are characterized with respect to the contents of different phases and the orientation relations between their crystallites and between them and the Si-substrate. For the reaction of Co films with Si$_{1-x}$C$_{x}$-substrates (x <= 0.005) it is shown that a rising carbon concentration of the Si-substrates leads to an increasing content of epitaxial crystallites in the CoSi$_{2}$-films formed. The reason for this is supposed to be the limitation of the Co diffusion caused by the carbon. The role played by carbon in diffusion processes in Si is discussed. The solid phase reaction of the metallic bi-layers Co/Ti and Co/Hf with Si(001)-substrates aimed at CoSi$_{2}$ epitaxy is analysed concerning the different effects produced by Ti and Hf as barrier-forming film materials. An intermediately appearing CoSi-phase with preferred orientations of its crystallites and the nucleation of the epitaxial CoSi$_{2}$, aimed at, at the CoSi/Si-interface were found. The higher quality of the epitaxial CoSi$_{2}$ obtained in the Co/Ti/Si-system is attributed to a more effective diffusion barrier in this film system, causing a higher CoSi$_{2}$ nucleation temperature. The found sequence of silicide phases is discussed taking into consideration thermodynamical, kinetical and structural aspects
Blanc, Nils. "Caractérisation structurale et magnétique de nanoparticules de CoPt : mise en évidence de la transition de phase A1 vers L10." Phd thesis, Université Claude Bernard - Lyon I, 2009. http://tel.archives-ouvertes.fr/tel-00466192.
Full textEnouz-Védrenne, Shaïma. "Elaboration et analyses structurales et chimiques de nanotubes hétéroatomiques de type C-N et C-B-N." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2007. http://tel.archives-ouvertes.fr/tel-00147980.
Full textIl a ainsi été mis en évidence dans ce manuscrit la possibilité de réaliser des nanotubes de type CNx et CBxNy mono- et multi-feuillets. Par ailleurs, une forte tendance à la ségrégation en domaines de type C et BN a été observée avec un localisation préférentielle et une taille des domaine spécifique, fonction de la technique de synthèse utilisée.
Allehyani, S. H. A., R. Seoudi, D. A. Said, A. R. Lashin, and A. Abouelsayed. "Synthesis, Characterization, and Size Control of Zinc Sulfide Nanoparticles Capped by Polyethylene Glycol." Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42490.
Full textLahouij, Imène. "Mécanismes de lubrification des nanoparticules à structure Fullerène : approche multi-échelle." Phd thesis, Ecole Centrale de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00790813.
Full textKuchibhatla, Satyanarayana. "PROBING AND TUNING THE SIZE, MORPHOLOGY, CHEMISTRY AND STRUCTURE OF NANOSCALE CERIUM OXIDE." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4250.
Full textPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science & Engr PhD
Mogilatenko, Anna. "Electron Microscopy Characterization of Manganese Silicide Layers on Silicon." Doctoral thesis, Universitätsbibliothek Chemnitz, 2003. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200300523.
Full textIn der vorliegenden Arbeit wird die Struktur von dünnen MnSi1.7-Schichten, die mit verschiedenen UHV-Herstellungsmethoden (template-Verfahren, reaktive Abscheidung und surfactant gesteuerte Abscheidung) auf (001)Si hergestellt wurden, mittels Elektronenmikroskopie charakterisiert. Die Ergebnisse der Elektronenbeugung an dünnen Mangansilicid-Schichten können vollständig interpretiert werden, wenn von den bekannten höheren Mangansiliciden (HMS) das Mn4Si7 als einzige vorliegende Phase angenommen wird. Der Hauptteil der Arbeit beschäftigt sich mit den mittels template-Verfahren abgeschiedenen Mn4Si7-Schichten. In diesen Experimenten wurde der Einfluss der template-Dicke auf die Morphologie und Orientierung der hergestellten Schichten untersucht. Es wird gezeigt, dass bei der Abscheidung von einer dünnen Mn-Schicht mit einer nominalen Dicke von 0,8 nm bei Raumtemperatur und weiterer Mn/Si-Koabscheidung bei einer Substrattemperatur von 550°C nahezu geschlossene Silicidschichten mit der bevorzugten Orientierungsbeziehung (110)[4-41]Mn4Si7 || (001)[110]Si entstehen. Weiterhin wachsen bei dieser template-Dicke Mn4Si7-Kristallite mit den Orientierungsbeziehungen: (3-38)[-443]Mn4Si7 || (001)[110]Si und (001)[110] Mn4Si7 || (001)[110]Si. Bei jeder gefundenen Orientierungsbeziehung treten beim Wachstum von Mn4Si7 auf (001)Si mehrere Domäne auf. Zusätzliche Experimente wurden unter Verwendung der reaktiven Schichtabscheidung durchgeführt. Sie verdeutlichen, dass bei reaktiver Abscheidung von Mn auf (001)Si ab einer Substrattemperatur von 600°C ein Wachstum von Mn4Si7-Inseln entlang den [110]-Richtungen des Siliciums erfolgt. XRD-Untersuchungen zeigen, dass diese Inseln die folgende Textur haben: (110)Mn4Si7 || (001)Si. Durch eine Modifizierung der Si-Oberfläche mit einer bis zu einer Monolage dicken Sb-Schicht (surfactant) kann das Mn4Si7-Inselwachstum beeinflusst werden. Die dabei gefundene Erhöhung der Mn4Si7-Inseldichte wird hier auf die reduzierte Mn- und Si-Diffusion zurükgeführt. Weiterhin wurde gefunden, dass dieser Abscheidungsprozess Mn4Si7-Kristallite der bevorzugten Orientierung (100)[010]Mn4Si7 || (001)[110]Si liefert
Coulon, Pierre-Eugène. "Films minces d'oxydes à grande permittivité pour la nanoélectronique : organisation structurale et chimique et propriétés diélectriques." Toulouse 3, 2009. http://thesesups.ups-tlse.fr/514/.
Full textDespite the considerable research work devoted since ten years to the study of new high permittivity (kappa) thin films for replacing silica in microelectronics, the relationships that exist between the structural/chemical and electrical properties of the films are not widely studied today. Thin Zr- and La-based oxide films, prepared by atomic layer deposition on silicon and/or germanium, are considered in this work. Quantitative parameters in relation with the organization at the nanometre level in the films and at the interfaces, determined by high resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS) operated on a modern electron microscope, are directly connected to electrical parameters such as kappa and Dit (interface state density). After annealing under vacuum, the La2O3 sesquioxide can be obtained with its high permittivity hexagonal phase (kappa ~ 27) but is not stable. It is hygroscopic and forms with the silicon substrate an extended amorphous interfacial layer silicate in composition. The LaxZr1-xO2-delta (x = 0. 2) ternary oxide is not hygroscopic. On a silicon substrate and with x ~ 0. 2, it is stabilized in the cubic structure (kappa ~ 30) with annealing and forms a silica-rich interfacial layer with a spatial extension limited to 1-2 nanometres. On a germanium substrate and with x ~ 0. 05, the ternary is stabilized with the high permittivity tetragonal structure (kappa ~ 40) due to germanium diffusion within the film and develops in direct contact with the substrate. Lanthanum is essentially present near the interface and forms a germanate that lowers the Dit. This work has been developed in line with the European program REALISE
Khadra, Ghassan. "Magnetic and structural properties of size-selected FeCo nanoparticle assemblies." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10145/document.
Full textOver the past few decades, use of nanostructures has become widely popular in the different field of science. Nanoparticles, in particular, are situated between the molecular level and bulk matter size. This size range gave rise to a wide variety physical phenomena that are still not quite understood. Magnetic nanoparticles are at their hype due to their applications in medical field, as a catalyst in a wide number of chemical reactions, in addition to their use for information storage devices and spintronics. In this work, we are interested in studying the intrinsic magnetic properties (magnetic moments and anisotropy) of FeCo nanoparticles. Thus, in order to completely understand their properties, mass-selected FeCo nanoparticles were prepared using the MS-LECBD (Mass Selected Low Energy Cluster Beam Deposition) technique in the sizes range of 2-6 nm and in − situ embedded in a matrix in order to separate them, to avoid coalescence during the annealing and to protect during transfer in air. From a first time, the structural properties (size, morphology, composition, crystallographic structure) of these nanopar- ticles were investigated in order to directly correlate the modification of the magnetic properties to the structure and chemical ordering of the nanoparticles after high temperature treatment. In addition to the bimetallic FeCo nanoparticles, reference Fe and Co systems were also fabricated and studied using the same techniques. The structural properties were investigated using high resolution transmission electron microscopy (HRTEM), anomalous x-ray diffraction (AXD) and extended x-ray absorption fine structure (EXAFS) where a phase transition from a disordered A2 phase to a chemically ordered CsCl B2 phase was observed and further validated from the magnetic findings using SQUID magnetometry and x-ray magnetic circular dichroism (XMCD)
Ramade, Julien. "Spectroscopie optique et microscopie électronique environnementale de nanoparticules Ag-In et Ag-Fe en présence de gaz réactifs." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1221/document.
Full textBimetallic nanoparticles (NPs) are known to present interesting catalytic properties justifying their use in several industrial processes in the domain of heterogeneous catalysis. However, their (chemical, geometrical, electronical) structure may evolve under realistic reactive atmosphere, involving a modification of their properties. In this multidisciplinary work, the aim is focused on the surface reactivity monitoring of these NPs under controlled gaseous environment. For this purpose, we developed an in situ spectrophotometer based on spatial modulation to monitor the structure evolution of a large assembly of NPs through the study of their localized surface plasmon resonance (LSPR). This global approach has been coupled with a more local approach by environmental transmission electronic microscopy (E-TEM). E-TEM observations have shown both composition and environmental effects on the chemical structure of Ag-In NPs. This structure evolves from a stable low-enriched indium alloy to a core@shell configuration with a shell composed of indium oxide as the indium atomic concentration increases. Furthermore, stable structure (core@shell, Janus, reduced system) domains were evidenced under reducing atmosphere, depending on the temperature and hydrogen pressure. Lastly, Ag-Fe NP oxido-reduction was monitored on the new setup through LSPR modifications. MET observations, environmental plasmonics and simulations (optical response, Monte-Carlo simulations) suggest that these metals are initially segregated, with an enriched-silver surface. The exposure to an oxidative atmosphere seems to induce the diffusion of iron onto the surface, followed by the formation of magnetite (Fe3O4)
Bugayeva, Natalia. "Synthesis and characterisation of CeO?, Sm?O? and Sm-doped CeO? nanoparticles with unique morphologies." University of Western Australia. School of Mechanical Engineering, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0012.
Full textHillion, Arnaud. "Études des propriétés magnétiques d'assemblées de nanoparticules de Co, FeRh et FeAu." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10155/document.
Full textNanomagnets are at the limit between a molecular complex and the bulk state. From a fundamental standpoint, the effects due to the small size of the system and particularly the increasing surface to volume ratio are likely to bring about new properties. Nanoparticles have found numerous applications in areas such as magnetic information storage, catalysis, biotechnology, medical diagnostics and energy. In this work, nanoparticles of 1.5 to 5 nm in diameter were synthesized by low energy cluster beam deposition (LECBD) and encapsulated in different matrices. As a first step, model systems based on cobalt nanoparticles strongly diluted in different matrices were fabricated in order to study more precisely the intrinsic properties of the nanomagnets. The continuation of this work consisted in increasing the concentration of nanoparticles in order to characterize the influence of interactions on the macroscopic magnetic behavior of the particles. Finally, after the development of tools to accurately determine the properties of model systems, these tools have been applied to bimetallic systems of significant theoretical and applicative interest (FeRh and FeAu). In particular, this work shows that after annealing under ultrahigh vacuum, the FeRh alloy nanoparticles in a carbon matrix show a phase transition A1 to B2 with no trace of pollution or coalescence. This transition has been demonstrated structurally by high resolution transmission electron microscopy (HRTEM) and magnetically by SQUID magnetometry and X-ray magnetic dichroism (XMCD)
Kovarik, Libor. "Microstructural study and modeling of metastable phases and their effect on strenghthening [sic] in Al-Mg-Cu-Si alloying system." The Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=osu1149006665.
Full textZhang, Yaoqing. "Exploring novel functionalities in oxide ion conductors with excess oxygen." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/2576.
Full textCharon, Emeline. "Géochimie et nanostructures des carbones des achondrites primitives : recherche de signatures pré-accrétionnelles par SIMS, Raman et METHR." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-01059791.
Full textHannour, Abdelkrim. "Réseaux bidimensionnels d'agrégats magnétiques préformés en phase gazeuse." Phd thesis, Université Claude Bernard - Lyon I, 2007. http://tel.archives-ouvertes.fr/tel-00139982.
Full textA1 vers la structure L10.
Drehmann, Rico. "Haftmechanismen kaltgasgespritzter Aluminiumschichten auf keramischen Oberflächen." Doctoral thesis, Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-229668.
Full textBonal, Lydie. "Matière organique et métamorphisme thermique dans les chondrites primitives." Phd thesis, Université Joseph Fourier (Grenoble), 2006. http://tel.archives-ouvertes.fr/tel-00120337.
Full textaltérants dans la nébuleuse proto-solaire et sur le Corps Parent (Altération Aqueuse, Métamorphisme
Thermique), qui ont perturbé les informations primaires. Le MT subi par les chondrites est ici abordé
à partir de la MO, transformée de façon irréversible sous l'effet du MT. La structure de la MO de plus
de 30 chondrites (CO3, CV3, UOC) a été quantifiée par spectrométrie Raman et la texture de certaines
par HRTEM. Minéralogie et pétrographie ont aussi été considérées. Un nouvel outil d'évaluation interclasse
du MT subi par les chondrites est défini : cohérent avec d'autres traceurs (concentration en
nanodiamants, pétrographie, composante P3), indépendant de l'AA, sensible à la Température de Pic de
Métamorphisme. Une TPM est évaluée pour les chondrites les plus métamorphisées : 330°C (Allende).
De nouveaux types pétrographiques sont attribués, les limitations de l'échelle pétrographique actuellement
définie soulignées. Une nouvelle est proposée, basée sur un paramètre spectral Raman. Certaines
caractéristiques pétrographiques sont réinterprétées. Ce travail montre que les précurseurs organiques
des chondrites ordinaires et carbonées (CO3, CV3) sont chimiquement et structuralement proches. Il
souligne la nécessité de prendre en compte les processus post-accrétion dans la compréhension des signatures
isotopiques (D, 15N), que des échanges isotopiques D-H ont eu lieu sur le CP, que la phase
porteuse de l'15N est très sensible aux processus secondaires. L'hypothèse de précurseurs interstellaires
de la MO chondritique est ici favorisée.
Kirschner, Holger. "HREM-Bildanalyse von III-V-Halbleiter-Schichtstrukturen durch quantitativen Bildvergleich Experiment - Simulation /." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961045167.
Full textBowden, Mark Edward. "Structural investigation of layered compounds based on the perovskite SrTiO₃." Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/251802.
Full textSaid, Aurore. "Matériaux Nanohybrides à Large Bande Interdite: Études de Synthèses, Propriétés et Applications." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00266833.
Full textHoudellier, Florent. "Contribution au développement du CBED et de l'holographie HREM pour l'analyse des déformations de couches épitaxiées." Toulouse, INSA, 2006. http://www.theses.fr/2006ISAT0014.
Full textEpitaxial thin layers undergo an elastic strain, related to the difference in lattice parameters, accompanied or not by chemical segregation. These various effects influence directly the properties of the epitaxial thin layers (emission in quantum wells, transport and magnetic anisotropy. . . ). They interest both fundamental research and applications aiming at adjusting the properties of epitaxial layers through the control of their state of strain. Most of the experimental techniques used to determine the lattice parameters in epitaxial layers only provide information averaged over the whole layer or its surface. On the contrary, Transmission electron microscopy (TEM) makes it possible to precisely select the studied zones, which is a considerable advantage in the presence of heterogeneities. In particular very accurate measurements can be obtained by convergent beam electron diffraction (CBED). This work aims at developing reliable methods to measure the strain in thin layers with a spatial resolution of the order of a nanometer. The selected systems for this study were SiGe=Si and GaInAs=GaAs epitaxial thin layers. CBED patterns obtained on cross-sectional specimens reveal a very heavy deformation in the layer and we observe, in the substrate, a strong evolution of the HOLZ line profile as a function of the distance between the studied zone and the interface. We showed that this evolution results from a free surface relaxation effect occurring in thin foils of strained specimens. This effect depends on many parameters, such as the thickness of the sample, the misfit and the distance between the studied zone and the interface. In order to retrieve the strain in the specimen, we developed a new method based on the combination of finite elements calculations and dynamical simulations obtained using an original formalism developed during this work and referred as TDDT (Time-Dependent Dynamical Theory). Elastic relaxation could also be observed in samples prepared in plan-view. The state of strain was thus determined in the various specimens through the comparison of simulated and experimental line profiles : remarkable agreements have been reached. These various measurements were compared with studies carried out by electron holography in HREM configuration making it possible to combine structural and chemical characterizations at an atomic scale. This works benefited from the use of a TEM-FEG instrument fitted with both a spherical aberration corrector and an energy filter
Chassagnon, Rémy. "Apports des simulations HREM et ELNES à la caractérisation interfaciale : cas de l'interface corindon/Mg2Si produite à l'état solide." Lyon, INSA, 2000. http://www.theses.fr/2000ISAL0103.
Full textThe study that we present fits in with a composite materials context where the interesting properties result from the monocristalline Al203-α ceramic particles insertion in aluminium based alloy Al(Mg, Si) able to develop a structural hardening process. However, the interfacial area (alloy in contact with the particles) is the seat of a thermodynamic evolution different from that in the bulk. The ceramic reinforcement is covered with Mg2Si precipitates in their stable thermodynamic phase. The adhesion of this compound is capital for the mechanical behaviour of the composite; its approach was carried out by a local cristallo-chemical characterization of the interface precipitate/reinforcement. Using a field emission electron microscope, two high spatial resolution techniques were implemented: the high resolution transmission electron microscopy imaging (HREM) and the local chemical analysis by electron energy loss spectroscopy (EELS). In HREM approach, the comparison between the experimental images and the simulated images, produced by several atomic models of the interface, highlighted the presence of the 0 and Si species at the interface. With regard to the second approach, we produced ELNES signatures of the Al, Mg, Si atoms in various environments as well by experimental acquisitions as by simulations of energy loss spectra of several Materials (aluminum, alumina, magnesium silicide). These ELNES simulations were led with the support of quantum chemistry codes for the calculation of the self-coherent potentials and of multiple scattering codes (ICXANES) used by the community of the physicists of the X spectroscopy. The results, obtained from the acquisition of the signatures in nanosonde mode, go in the direction of the model retained by HREM
Narain, Krishna. "High resolution electron microscopy (HREM) studies of the sulphidisation of palladium and palladium alloy particles on self- supporting γ-alumina." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627555.
Full textShafeie, Samrand. "Properties in New Complex Perovskite-Related Materials, a Matter of Composition and Structure." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-88793.
Full textMutta, G. R. "Propriétés structurales, optiques et électroniques des couches d'InN et hétérostructures riches en indium pour applications optoélectroniques." Phd thesis, Université de Caen, 2012. http://tel.archives-ouvertes.fr/tel-00779495.
Full textKolahdouz, Esfahani Mohammadreza. "Application of SiGe(C) in high performance MOSFETs and infrared detectors." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32049.
Full textQC 20110405
Gallina, Pavel. "Využití kovové sondy pro ovládání optických procesů a zobrazování v blízkém poli." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382288.
Full text林信余. "HRTEM/EELS Analyses of Chromium Oxide Nanowires." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/76273981070218390488.
Full textChu, Chia Chi, and 朱家琦. "HRTEM Study to Al2O3 SIGMA 7 Grain Boundary." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/65482609742576992397.
Full textRajagopalan, Srivaramangai. "Effect of imaging conditions for reliable measurement of local strain from synthetic High Resolution Transmission Electron Microscope (HRTEM) images by Geometrical Phase Analysis (GPA)." Thesis, 2009. http://hdl.handle.net/2152/ETD-UT-2009-12-586.
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Tsai, Kuen Rong, and 蔡坤榮. "HRTEM Analysis and Magnetic Properties Study of Surface Oxidizing and Nitriding of Nanocrystalline Iron Particles." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/26302346331702818839.
Full text大同工學院
材料科學(工程)研究所
81
Ultrafine particles of Fe were produced by using gas condensation method. Pure oxygen, air and nitrogen were introduced into the as-evaporate particles before they were taken out from chamber. Change atmosphere produces different layer structure around Fe. The crystal structure was identified by using high resolution electron transmission microscope( HRTEM) and image analysis technique. The conventional transmission electron microscope (TEM) was also use to check the result from the HRTEM. The average particle size was carried out by using BET nitrogen adsorption method and magnetic properties will be determined by VSM. The results indicate that the mean particle size of Fe increases as the absolute He pressure increasing. When the pressure changed from 1 mbar to 100 mbar, the mean particle of Fe varied from about 13 nm to 40 nm and a maximum value of coercivity about 1262 Oe was observed at the critical mean particle size of 20 nm. A layer of amorphous structure was formed initially. After the annealing under the electron irradiation this layer crystallized into ferrosoferric oxide or gamma-ferric oxide if the atmosphere was pure oxygen or air, but it formed a passivated layer of zeta-iron nitride when nitrogen was introduced. In attempt to investigate the effect of oxide on magnetic properties, a hydrogen reducing process was employed to remove the oxide layer. It was found that the clean surface leads to the increasing of the coercivity and magnetization at room temperature, but the change is not significant. However, the field required to saturate the particles without the oxide layer increases.
Lin, Chih-Jen, and 林智仁. "HRTEM STUDY OF THE DIFFUSION IN Si/Ta/NiFe/Cu/Co/FeMn/Ta SPIN VALVE STRUCTURE." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/21672186644640531718.
Full text國立清華大學
工程與系統科學系
88
Since the discovery of the giant-magneoresistance (GMR) effect (1) in magnetic thin film structures, giant-magneoresistance spin-valve structures have been promising candidates for high-density magnetic recording read head sensors. A significant concern for the performance of these read head sensors is the thermal stability. Long-term operation under a high current density causes thermal degradation and interdiffusion of multilayers. Previous studies of the effect of annealing on the spin-valve multilayers were carried out using X-ray reflectivity (2) and nuclear magnetic resonance (NMR) (3). However in most studies, they only offered the average of interface mixing over the film plane. The microstructure information plays an important role in the diffusion mechanism of the spin-valve structure. In viewpoint of microstructure, the major concerns in spin-valve multilayers are the identity of the phases, the texture, the grain size, the roughness of the individual layer, and the interfacial structure between each layer. In our work, we used a field emission gun transmission electron microscope (FEGTEM) with energy dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) to investigate the microstructure and composition distribution of the spin-valve ultra thin film structures.
Moradifar, P., B. Bahman-Nezhad, M. Abdorahim, S. Darvish, and S. Asgari. "The SiC/SiO Nanostructured Core-Shell as Anode Material for Lithium Ion Batteries: Synthesis and HRTEM Characterization." Thesis, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35252.
Full textBartel, Til Pierre [Verfasser]. "Chemical inhomogeneity in InxGa1-xN and ZnO a HRTEM study on atomic scale clustering / vorgelegt von Til Pierre Bartel." 2008. http://d-nb.info/988226529/34.
Full textTsai, Shuo-Cheng, and 蔡碩承. "Lifetime Evaluation of Nuclear Grade Graphite in Advanced Very High Temperature Gas-cooled Reactor(VHTR) Core Environment Using HRTEM Microstructural Analysis." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/90037126645186268046.
Full text國立清華大學
工程與系統科學系
101
In this work, Nuclear grade graphite were irradiated by 3 MeV C2+ ion under high temperatures(>600℃) and ultrahigh vacuum (<5x10-7torr) environment to simulate the same radiation damage level in High Temperature Gas-Cooled Reactor(HTGR) environment. Graphite {0002} and {21 ̅1 ̅0} plane were investigated by FEG-TEM high resolution images. Fast Fourier transform was applied to calculate the average lattice parameters after irradiation. Microstructural evolution analyzed in this study including change of lattice parameters、disorder coefficients were intergraded with structure factor、pore generation factor to develop a model for lifetime and volume change evaluation inside nuclear grade graphite after different irradiation temperatures and fluences. Our model estimated that IG-110 irradiated at 600℃, its maximum volume change reached -6.02% and its lifetime is about 30.5dpa which is very close to experiment carried by neutron. For ATR-2E graphite, its lifetime reaches 25.5dpa in the same irradiated temperature(600℃). At higher irradiated temperature (800), both the lifetime of two graphite decayed seriously. (lifetime is 25.5dpa for IG-110 and 18.5dpa for ATR-2E). According to calculation, graphite block in the highest irradiation fluence region should be replaced every 5 years to insure the structural integrity under irradiation. Another part of this study showed calculation results of the energy storage inside graphite at high temperature irradiation. At high temperature irradiation condition(>600℃), stored energy is less than 10cal/g. This value is quite small compared to previous study (500cal/g at 150℃). From our results, energy storage in graphite would no longer be a problem in VHTR environment.