Solar absorber coatings are one of the key components in concentrated solar power (CSP) plants. Currently operating at temperatures up to 565°C and suffering from emissive losses, their energy conversion efficiency could be improved by applying high-temperature stable materials with solar selective properties, i.e. high absorptivity and low emissivity. In this work, the transparent conductive oxide (TCO) SnO2:Ta is developed as a solar selective coating (SSC) for CSP absorbers. Starting with simulations covering basic requirements for SSCs, the deposition process of SnO2:Ta is optimized and extensive optical characterization and modelling are performed. It is shown that upon covering with a SiO2 antireflective layer, a calculated absorptivity of 95% and an emissivity of 30% are achieved for the model configuration of SnO2:Ta on top of a perfect black body (BB). High-temperature stability of the developed TCO up to 800 °C is shown in situ by spectroscopic ellipsometry and Rutherford backscattering spectrometry. The universality of the concept is then demonstrated by transforming silicon and glassy carbon from non-selective into solar selective absorbers by depositing the TCO on top of them. Finally, the energy conversion efficiencies ηCSP of SnO2:Ta on top of a BB and an ideal non-selective BB absorber are compared as a function of solar concentration factor C and absorber temperature TH.

Der Verzehr von Pflaumen ist derzeit sehr gering. Häufig wird unbefriedigende Fruchtqualität aufgrund unreif geernteter Früchte als Ursache genannt. Um eine hohe Fruchtqualität zu erzeugen ist es nötig, Vorerntebedingungen wie Fruchtbehang und Bodeneigenschaften optimal zu gestalten und die Früchte im richtigen Reifestadium zu ernten. Die Ziele dieses Projektes waren daher 1. die Untersuchung des Einflusses und interaktiver Effekte von Bodeneigenschaften, Fruchtbehang und Baumwasserzustand auf die Qualität von ''Jojo'' und ''Tophit plus'' Pflaumen. 2. den Effekt unterschiedlicher Pflücktermine auf die innere und äußere Fruchtqualität zu bewerten. 3. das Potenzial der Laserlichtrückstreubildanalyse als neues zerstörungsfreies Verfahren zur Bewertung der Fruchtqualität abzuschätzen. Die Untersuchungen wurden 2011 bis 2013 durchgeführt. Zur Bewertung der Vorernteeinflüsse wurden Früchte dreimal vor sowie am kommerziellen Erntetermin geerntet und im Labor untersucht. Dann wurden sie für 28 Tage bei 2°C und zusätzlich 2 Tage bei 20°C bei 90% rF gelagert. Während dieser Zeit wurden Früchte jeder Behandlungsgruppe nach 0, 7, 14, 21, 28 und 30 Tagen analysiert. Früchte von Bäumen mit geringerem Fruchtbehang von Böden mit geringen ECa Werten wiesen die höchsten SSC und Trockenmassegehalte, solche von Bäumen mit geringem Fruchtbehang und von Böden mit hohem ECa die höchste Frischmasse auf. Gut wasserversorgte Bäume hatten niedrigere Fruchterträge, ihre Früchte transpirierten verstärkt und hatten geringere Zucker- und Trockenmassegehalte als Pflaumen von Bäumen mit schlechter Wasserversorgung. Die späten Ernte von ''Jojo'' Pflaumen, vorzugsweise ca. 137 Tage nach der Vollblüte, ergab die beste Fruchtqualität. Diese Früchte besaßen die höchste Frischmasse und die geringste Transpiration. Laserlichtrückstreumessungen bei 532 und 785 nm zeigten, dass diese zerstörungsfreie Methode für die Analyse von Qualitätsparametern wie Anthocyangehalt und Fruchtfleischfestigkeit gut geeignet ist. / Plum consumption does not meet its potential, most probably because of a non-uniform fruit quality and lack of fully-mature fruit. It is necessary to manage preharvest conditions such as crop load and soil properties optimally in order to obtain high quality plums and to harvest the fruit in ripe stage. In this study, (1) the effects of soil ECa, crop load and maximum daily trunk shrinkage (MDS) on various fruit quality parameters of two European plum cultivars ''Jojo'' und ''Tophit plus'') (2) the internal and external fruit quality as it relates to harvest time were investigated. The investigation of plums was carried out in an experimental orchard in 2011, 2012 and 2013. Fruit of selected trees were sampled and subjected to laboratory measurements three times before and at the commercial harvest. At the commercial harvest, plums were stored at 2 °C and 90% RH for up to 28 days plus 2 days at 20 °C. During storage, fruit of each treatment were sampled after 0, 7, 14, 21, 28 and 30 days in order to analyse the physicochemical quality. In addition, the optical properties of samples were non-destructively evaluated through laser light backscattering imaging (LLBI). Fruit from low crop load trees grown under low ECa had the highest SSC and dry matter content, while those from low crop load trees under high ECa showed the highest fresh mass in 2013. Moreover, low MDS trees had lower total fruit yield, and fruit had higher transpiration, lower SSC, and dry matter content than those grown on trees with high MDS. Fruit quality was best when plums had been harvested late, preferably at the 3rd harvest date (137 DAFB) in this study. These fruit had the highest fresh mass and lowest transpiration. Furthermore, the results of LLBI measured at 532 nm and 785 nm showed an encouraging potential to predict quality parameters of plums such as anthocyanin content and fruit firmness.

Thin-film transistors (TFTs) are primarily used as a switching element in liquid crystal displays. Currently, amorphous silicon is the dominant TFT technology for displays, but higher performance TFTs will become necessary to enable ultra-definition resolution high-frequency large-area displays. Amorphous zinc tin oxide (ZTO) TFTs were fabricated by RF magnetron sputter deposition. In this study, the effect of both deposition and post annealing conditions have been evaluated in regards to film structure, composition, surface contamination, and device performance. Both the variation of oxygen partial pressure during deposition and the temperature of the post-deposition annealing were found to have a significant impact on TFT properties. X-ray diffraction data indicated that the ZTO films remain amorphous even after annealing to 600° C. Rutherford backscattering spectrometry indicated that the Zn:Sn ratio of the films was ~1.7:1 which is slightly tin rich compared to the sputter target composition. X-ray photoelectron spectroscopy data indicated that the films had significant surface contamination and that the Zn:Sn ratios changed depending on sample annealing conditions. Electrical characterization of ZTO films using TFT test structures indicated that mobilities as high as 17 cm² V⁻¹ s⁻¹ could be obtained for depletion mode devices. It was determined that the electrical properties of ZTO films can be precisely controlled by varying the deposition conditions and annealing temperature. It was found that the ZTO electrical properties could be controlled where insulating, semiconducting and conducting films could be prepared. This precise control of electrical properties allowed us to incorporate sputter deposited ZTO films into resistive random access memory (RRAM) devices. RRAM are two terminal nonvolatile data memory devices that are very promising for the replacement of silicon-based Flash. These devices exhibited resistive switching between high-resistance states to low-resistance states and low-resistance states to high-resistance states depending on polarity of applied voltages and current compliance settings. The device switching was fundamentally related to the defect states and material properties of metal and insulator layers, and their interfaces in the metalinsulator-metal (MIM) structure. / Graduation date: 2012 / Access restricted to the OSU Community at author's request from Jan. 6, 2012 - Jan. 6, 2013

La nécessité de prouver l’existence de nouvelles particules comme les quarks et le boson de Higgs a entrainé le développement de deux nouveaux pans de la recherche : la physique des hautes énergies ou physique des particules, dédiée à prouver expérimentalement l'existence de ces particules puis à étudier leurs propriétés et la physique des accélérateurs, dédiée au développement de nouveaux instruments pour la physique des hautes énergies.Dans ce contexte, des collisionneurs linéaires électrons/positrons polarisés de forte luminosité dont l'énergie serait connue et accordable pourrait permettre d’étudier plus finement des particules se situant dans des énergies autour du TeV telles que le Boson de Higgs. C'est dans ce sens que le projet International Linear Collider (ILC) est conçu et c'est dans le cadre du développement de ce collisionneur linéaire de particules que cette thèse de doctorat se situe. Un des points critiques de l'ILC est la source de positrons polarisés. Sans entrer dans des explications sur la physique du processus de création de positrons polarisés, nous précisons simplement que ceux-ci sont créés lorsque des rayons gamma polarisés circulairement interagissent avec la matière. Le point critique est donc la source de rayons gamma polarisés circulairement. Une alternative pour cette source est la diffusion Compton inverse et c'est finalement dans le cadre de la recherche et du développement de systèmes lasers de fortes puissances moyennes asservis à des cavités Fabry-Perot pour la production de rayons gamma polarisés par diffusion Compton inverse que se situe cette thèse.Dans un premier temps, nous posons plus précisément le contexte de cette thèse, le principe de la diffusion Compton inverse ainsi que le choix d’une architecture optique basée sur un laser fibré et une cavité Fabry-Perot. Nous finissons sur une énumération des différentes applications possibles de la diffusion Compton inverse montrant que les travaux présentés pourraient bénéficier de transfert technologique vers d’autres domaines. Dans un second temps, nous présentons les différentes architectures d’amplification laser fibrée étudiées ainsi que les résultats obtenus. Dans un troisième temps, nous faisons un rappel du principe de fonctionnement d’une cavité Fabry-Perot et présentons celle utilisée pour notre expérience ainsi que ses spécificités. Dans un quatrième temps, nous abordons l’expérience de diffusion Compton inverse qui nous a permis de présenter pour la première fois à notre connaissance l’utilisation conjointe d’un laser à fibre optique et d’une cavité Fabry-Perot dans le cadre d’un accélérateur de particules pour générer des rayons gamma. Le dispositif expérimental ainsi que les résultats obtenus sont alors présentés. Finalement, nous résumons les résultats présentés dans ce manuscrit et proposons différentes possibilités d’évolution pour le système dans une conclusion générale. / The requirement to prove the existence of news particles like quarks and the Higgs boson has led the development of two news branches for the research: the high energy physics or particle physics, dedicated to experimentally prove the existence of these new particles then to study their properties and the accelerator physics, dedicated to develop particles accelerators for the high energy physic. In this context, polarized electrons/positrons high luminosity linear collider of known and scalable energy might enable more precise studies of particles with energy around the TeV such as the Higgs boson. To that end, the International Linear Collider (ILC) project is being designed and it is in this framework that this PhD thesis takes place. One of the critical points of the ILC is the polarized positrons source. Without going through further explanation on the physical process of polarized positrons production, we point out that they are produced when circularly polarized gamma rays interact with mater. Thus, the critical point is the circularly polarized gamma-ray source. A technical solution for this source is the Compton backscattering and in the end, this thesis takes place in the framework of R&D for high average power laser systems enslaved to Fabry-Perot cavities for polarized gamma-ray production by Compton backscattering. In the first part, we present this thesis context, the Compton backscattering principle and the choice for an optical architecture based on a fiber laser and a Fabry-Perot cavity. We finish by enumerating several possible applications for Compton backscattering which shows that the work presented here might benefits from technology transfer through others research fields. In the second part, we present the different fiber laser architecture studied as well as the results obtained. In the third part, we remind the operating principle of a Fabry-Perot cavity and present the one used for our experiment as well as its specificities. In the fourth part, we address the Compton backscattering experiment which enables us to present the joint utilization of a fiber laser and a Fabry-Perot cavity in a particles accelerator to generate gamma rays for the first time to our knowledge. The experimental apparatus as well as the results obtained are thus presented. In the end, we summarize the results presented in this manuscript and propose different evolution possibilities for the system in a general conclusion.

La spectroscopie EPES (Elastic Peak Electron Spectroscopy) permet de mesurer le pourcentage he d’électrons rétrodiffusés élastiquement par la surface d’un échantillon soumis à un bombardement électronique. C’est une méthode non destructive et extrêmement sensible à la surface. L'objectif de ce travail est de modéliser le cheminement des électrons élastiques dans la matière grâce à une simulation informatique basée sur la méthode Monte Carlo. Cette simulation contribue de manière essentielle à la connaissance et à l'interprétation des résultats expérimentaux obtenus par spectroscopie EPES. Nous avons, de plus, adapté cette simulation à différentes surfaces transformées à l’échelle micrométrique et nanométrique. A l’aide d’une méthode originale, basée sur une description couche par couche du matériau, j’ai réalisé un programme informatique (MC1) rendant compte du cheminement des électrons élastiques dans les différentes couches du matériau. Le nombre d’électrons ressortant de la surface dépend de nombreux paramètres comme : la nature du matériau à étudier, l’énergie des électrons incidents, l’angle d’incidence, les angles de collection des analyseurs. De plus, je me suis intéressé à l’effet de la rugosité de la surface et j’ai démontré qu’elle joue un rôle déterminant sur l’intensité du pic élastique. Ensuite, grâce à l’association de la spectroscopie EPES et de la simulation Monte Carlo, j’ai déduit les modes de croissance de l’or sur substrat d’argent et de cuivre. Les effets de l’arrangement atomique et des pertes énergétiques de surfaces ont ensuite été étudiés. Pour cela, une deuxième simulation MC2 tenant compte de ces deux paramètres a été réalisée permettant d’étudier les surfaces à l’échelle nanométriques. Ces paramètres jusqu’alors non pris en compte dans notre simulation MC1, joue un rôle essentiel sur l’intensité élastique. Ensuite, j’ai obtenu une formulation simple et exploitable pour l’interprétation des résultats obtenus par la simulation MC2 pour un analyseur RFA. Afin de valider, les différents résultats de la simulationMC2, j’ai réalisé des surfaces de silicium nanostructurées, à l’aide de masques d’oxyde d’alumine réalisés par voie électrochimique. J’ai pu créer des nano-pores par bombardement ionique sous ultravide sur des surfaces de silicium. Afin de contrôler la morphologie de la surface, j’ai effectué de l’imagerie MEB ex-situ. La simulation Monte Carlo développée associée aux résultats EPES expérimentaux permet d’estimer la profondeur, le diamètre et la morphologie des pores sans avoir recours à d’autres techniques ex-situ.Cette simulation MC2 permet de connaître la surface étudiée à l’échelle nanométrique. / EPES (Elastic Peak Electron Spectroscopy) allows measuring the percentage he of elastically backscattered electrons from the surface excited by an electron beam. This is a non destructive method which is very sensitive to the surface region. The aim of this work is to model the trajectory of elastic electrons in the matter with a computer simulation based on Monte Carlo method. This simulation allows interpreting experimental results of the EPES spectroscopy. We have moreover adapted this simulation for different surfaces transformed to micrometer and nanometer scales. Using an original method, based on a description of material layer by layer, I realized a computer program (MC1) that takes into account the path of elastic electrons in different layers of material. The number of electrons emerging from the surface depends on many parameters such as: the electron primary energy, the nature of the material, the incidence angle and the collection angles of the analyzer. In addition, I was interested in the effect of surface roughness and I showed that it plays an important role in the intensity of the elastic peak. Then, through an association of the EPES and the Monte Carlo simulation results, I deduced the growth patterns of gold on silver and copper substrates. The effects of the atomic arrangement and the surface excitations were then studied. For this, a new simulation MC2 that takes into account these two parameters has been developed to study nanoscale surfaces. These parameters not previously included in our MC1simulation play a important role in the elastic intensity. Then I have got a simple formula for interpreting the results obtained by the simulation for a RFA analyzer. To validate the different results of the simulation MC2, I realized nano-structured silicon surfaces, using aluminium oxide masks. Nano-pores have been created by Ar+ ions bombardment in UHV chamber on silicon surfaces.To control the morphology of the surfaces, I realized SEM images (Techinauv Casimir) ex-situ. The Monte Carlo simulations, developed here, associated with the EPES experimental results can estimate the depth, the diameter, the morphology of pores without the help of other ex-situ techniques.

Dans le cadre de la mission spatiale SMOS (Soil Moisture and Ocean Salinity), nous présentons dans cette thèse une nouvelle approche numérique de modélisation du calcul de l’émissivité et du coefficient bi-statique de systèmes forestiers sol-litière en Bande L. Le système sol-litière est représenté par deux couches diélectriques 3D comportant des interfaces rugueuses, une démarche qui n’apparait pas actuellement dans la littérature. Nous validons notre approche pour une seule couche en comparant les simulations de l'émissivité avec celles produites par la méthode des moments et des données expérimentales. A partir de ce nouveau modèle, nous évaluons la sensibilité de l’émissivité du système sol-litière en fonction de l’humidité et de la rugosité de la litière. Ce nouveau modèle permettra de créer une base de données synthétiques d’émissivités calculées en fonction de nombreux paramètres qui contribuera à améliorer la prise en compte de la litière dans l'algorithme d’inversion des données de la mission spatiale SMOS. / In the context of the SMOS (Soil Moisture and Ocean Salinity) mission, we present a new numerical modelling approach for calculating the emissivity and bistatic scattering coefficient of the soil-litter system found in forests, at L-band. The soil-litter system is modelled as two 3-dimensional dielectric layers, each with a randomly rough surface, which to our knowledge has not previously been achieved. We investigate the validity of the approach for a single layer by comparing emissivity simulations with results of Method of Moments simulations, and experimental data. We then use the approach to evaluate the sensitivity of the soil-litter system as a function of moisture content and the roughness of the litter layer. The numerical modelling approach which has been developed will allow us in the future to create a synthetic database of the emissivity of the soil-litter system as a function of numerous parameters, which will contribute to validating and improving the inversion algorithm used by the SMOS mission to retrieve soil moisture over forests.

This thesis presents the work done on electronic transport in various interacting and non-interacting systems in one and two dimensions. The systems under study are: an interacting quantum dot [1], a non-interacting quantum wire and a ring in which time-dependent potentials are applied [2], an interacting quantum wire and networks of multiple quantum wires with resistive regions [3, 4], one-dimensional edge stages of a two-dimensional topological insulator [5], and a hybrid system of two-dimensional surface states of a three-dimensional topological insulator and a superconductor [6]. In the first chapter, we introduce a number of concepts which are used in the rest of the thesis, such as scattering theory, Landauer conductance formula, quantum wires, bosonization, topological insulators and superconductor. In the second chapter, we study transport through a quantum dot with interacting electrons which is connected to two reservoirs. The quantum dot is modeled by two sites within a tight-binding model with spinless electrons. Using the Lippman-Schwinger method, we write down an exact two-particle wave function for the dot-reservoir system with the interaction localized in the region of the dot. We discuss the phenomena of two-particle resonance and rectification. In the third chapter, we study pumping in two kinds of one-dimensional systems: (i) an infinite line connected to reservoirs at the two ends, and (ii) an isolated ring. The infinite line is modeled by the Dirac equation with two time-independent point-like backscatterers that create a resonant barrier. We demonstrate that even if the reservoirs are at the same chemical potential, a net current can be driven through the channel by the application of one or more time-dependent point-like potentials. When the left-right symmetry is broken, a net current can be pumped from one reservoir to the other by applying a time-varying potential at only one site. For a finite ring, we model the system by a tight-binding model. The ring is isolated in the sense that it is not connected to any reservoir or environment. The system is driven by one or more time-varying on-site potentials. We develop an exact method to calculate the current averaged over an infinite amount of time by converting it to the calculation of the current carried by certain states averaged over just one time period. Using this method, we demonstrate that an oscillating potential at only one site cannot pump charge, and oscillating potentials at two or more sites are necessary to pump charge. Further we study the dependence of the pumped current on the phases and the amplitudes of the oscillating potentials at two sites. In the fourth chapter, we study the effect of resistances present in an extended region in a one-dimensional quantum wire described by a Tomonaga-Luttinger liquid model. We combine the concept of a Rayleigh dissipation function with the technique of bosonization to model the dissipative region. In the DC limit, we find that the resistance of the dissipative patch adds in series to the contact resistance. Using a current splitting matrix M to describe junctions, we study in detail the conductances of: a three-wire junction with resistances and a parallel combination of resistances. The conductance and power dissipated in these networks depend in general on the resistances and the current splitting matrices that make up the network. We also show that the idea of a Rayleigh dissipation function can be extended to couple two wires; this gives rise to a finite transconductance analogous to the Coulomb drag. In the fifth chapter, we study the effect of a Zeeman field coupled to the edge states of a two-dimensional topological insulator. These edge states form two one-dimensional channels with spin-momentum locking which are protected by time-reversal symmetry. We study what happens when time-reversal symmetry is broken by a magnetic field which is Zeeman-coupled to the edge states. We show that a magnetic field over a finite region leads to Fabry-P´erot type resonances and the conductance can be controlled by changing the direction of the magnetic field. We also study the effect of a static impurity in the patch that can backscatter electrons in the presence of a magnetic field. In the sixth chapter, we use the Blonder-Tinkham-Klapwijk formalism to study trans-port across a line junction lying between two orthogonal topological insulator surfaces and a superconductor (which can have either s-wave or p-wave pairing). The charge and spin conductances across such a junction and their behaviors as a function of the bias voltage applied across the junction and various junction parameters are studied. Our study reveals that in addition to the zero conductance bias peak, there is a non-zero spin conductance for some particular spin states of the triplet Cooper pairs. We also find an unusual satellite peak (in addition to the usual zero bias peak) in the spin conductance for a p-wave symmetry of the superconductor order parameter.

This work reports on the cobalt pyridinoporphyrazinate (CoTmtppa) as a platinum-group metal-free catalyst for hydrogen evolution and oxidation reactions with the possibility of use in hydrogen energy and hydrogen potentiometric sensing. A different interaction of CoTmtppa with various electrode substrates, highly oriented pyrolytic graphite (HOPG) and annealed gold (Au(111)), affects its electrocatalytic behaviour in hydrogen reactions. The formation of a hydride-type complex with the bonding of hydrogen atoms to cobalt centre is supposed to be the rate-determining step. In the case of hydrogen evolution, the maximum catalytic activity of mediator was reached at pH = 11,0, when the HOPG/CoTmtppa showed overpotential decrease by 300 mV and an almost 60-fold increase of current densities compared to HOPG. The electrocatalytic activity of Au(111)/CoTmtppa resulted in a further decrease of overpotential by 175 mV in comparison with HOPG/Co(I)Tmtppa. The electrochemical oxidation of hydrogen was found to depend on hydrogen source which was electrochemically generated on-site or molecular hydrogen supplied from an external source. In the case of electrochemically generated hydrogen, the maximum activity of HOPG/CoTmtppa was reached at pH = 2.1 and an additional it was observed 50 % increase in current...

Transition metal interface effects of on the crystallization of carbon and silicon were investigated. The graphitization of carbon was studied by ion beam sputter deposition of atomic carbon onto a nickel surface at temperatures ranging from room temperature to 550 °C. The resulting films were characterized by X-ray photoelectron spectroscopy, nuclear reaction analysis combined with Rutherford backscattering spectrometry, Raman spectroscopy and transmission electron microscopy. A temperature-induced and a nickel-induced effect on the graphitic ordering is demonstrated. The carbon films showed a two layered structure: directly on the nickel surface up to 8 monolayers of graphitic carbon, further deposited carbon formed less ordered structures, preferably perpendicular to the surface. The results are discussed on the basis of hyperthermal atom deposition, surface diffusion, metal-induced crystallization and dissolution-precipitation. The analysis points to a dominating role of surface diffusion-assisted crystallization in the carbon ordering process. The kinetics of silver-induced crystallization of amorphous silicon were studied in a series of isothermal annealing experiments at 350 °C, 400 °C, 450 °C and 500 °C. The annealing process was monitored in situ employing Raman spectroscopy and Rutherford backscattering spectrometry from which time resolved information on the phase transformation and hence the kinetics are obtained. The grain structure of the crystallized silicon film was investigated with optical and scanning electron microscopy which reveals grain diameters of 5 to 8 µm. The small scale crystallinity was measured with X-ray diffraction and crystal domain sizes from 20 to 50 nm were observed. The phase transformation kinetics are discussed based on the Johnson-Mehl-Avrami-Kolmogorov theory. The analysis points to a two-dimensional, diffusion limited process with fast Avrami-type nucleation and an activation energy of 0.8 eV/at.:Contents 1. Introduction 2. Metal-Induced Crystallization 2.1. Introduction and State of the Art of Metal-Induced Crystalliza-tion 2.2. Thermodynamics of Metal-Induced Crystallization 2.3. Kinetics of Metal-Induced Crystallization 3. Ion Beam Analysis 3.1. Rutherford Backscattering Spectrometry 3.2. Nuclear Reaction Analysis 4. Raman Spectroscopy 4.1. Light Scattering in Solids 4.2. Theory 4.2.1. The Raman Spectrum of Graphitic Carbon 4.2.2. The Silicon Raman Spectrum 5. The Cluster Tool at the Ion Beam Center 5.1. General Concept 5.2. Sputtering Chamber 5.3. The Environmental Chamber 5.4. The Analysis Chamber 5.5. The Ion Beam Analysis Chamber 5.5.1. The Experimental Setup 6. The Carbon Nickel System 6.1. Experimental Details 6.1.1. Film growth 6.1.2. Characterization 6.2. Results 6.3. Discussion 7. The Silicon Silver System 7.1. Experimental 7.1.1. Film Preparation 7.1.2. In Situ Raman Spectroscopy 7.1.3. In Situ Rutherford Backscattering Spectrometry 7.2. Results 7.2.1. Raman Spectroscopy 7.2.2. Rutherford Backscattering Spectrometry 7.2.3. X-ray Diffraction 7.2.4. Optical and Scanning Electron Microscopy 7.3. Discussion 8. Conclusion and Outlook A. Appendix A.1. Spectroscopic Lineshapes A.1.1. The Lorentzian Lineshape A.1.2. The Breit-Wigner-Fano Lineshape A.1.3. The Doniach-Sunjic Lineshape A.1.4. The Gaussian Lineshape A.1.5. The Voigt Lineshape A.2. Statistcial Distribution Functions A.2.1. The Gamma Distribution Bibliography / Der Einfluss von Übergangsmetallkontaktflächen auf die Kristallisation von Kohlenstoff und Silizium wurde untersucht. Dazu wurde Kohlenstoff bei Temperaturen von Raumtemperatur bis 550 °C auf Nickel mittels Ionenstrahl-Sputtern abgeschieden. Die so erzeugten Filme wurden mit Röntgenphotoelektronen Spektroskopie, Kernreaktionsanalyse kombiniert mit Rutherford Rückstreu Spektrometrie, Raman Spektroskopie und Transmissions-Elektronenmikroskopie charakterisiert. Ein Nickel- und ein Temperatureffekt auf den Graphitisierungsprozess wird nachgewiesen. Die Kohlenstofffilme zeigten einen zweilagigen Aufbau: Direkt auf der Nickeloberfläche bis zu 8 Monolagen graphitischen Kohlenstoffs, weiterer abgeschiedener Kohlenstoff bildet weniger geordnete Strukturen, die bevorzugt senkrecht zur Oberfläche ausgerichtet sind. Die Ergebnisse werden auf Basis von hyperthermischer, atomarer Abscheidung, Oberflächendiffusion, Metall-induzierte Kristallisation und Lösung-Ausfällung diskutiert. Die Analysen deuten auf eine dominante Rolle der Oberflächendiffusion im Graphitisierungsprozess hin. Die Kinetik der Silber-induzierten Kristallisation von amorphen Silizium wurde in einer Reihe von isothermalen Temperexperimenten bei 350 °C, 400 °C, 450 °C und 500 °C untersucht. Der Tempervorgang wurde mit in situ Raman Spektroskopie und in situ Rutherford Rückstreu Spektrometrie charakterisiert, wodurch zeitaufgelöste Information über den Phasenübergang und damit die Kinetik gewonnen wurden. Das Gefüge der entstandenen Siliziumschichten wurde mit optischer und Rasterelektronenmikroskopie untersucht, welche Korndurchmesser von 5 bis 8 µm zeigten. Die Kristallinität wurde mit Röntgendiffraktometrie analysiert. Hierdurch wurden Kristallitgrößen von 20 bis 50 nm bestimmt. Die Kinetik des Phasenüberganges wird anhand der Johnson-Mehl-Avrami-Kolmogorov Theorie diskutiert. Dies deutet auf einen zeidimensionalen, diffusionslimitierten Prozess mit schnell abklingender Avrami-Keimbildung hin. Die Aktivierungsenergie wurde zu 0.8 eV/At. bestimmt.:Contents 1. Introduction 2. Metal-Induced Crystallization 2.1. Introduction and State of the Art of Metal-Induced Crystalliza-tion 2.2. Thermodynamics of Metal-Induced Crystallization 2.3. Kinetics of Metal-Induced Crystallization 3. Ion Beam Analysis 3.1. Rutherford Backscattering Spectrometry 3.2. Nuclear Reaction Analysis 4. Raman Spectroscopy 4.1. Light Scattering in Solids 4.2. Theory 4.2.1. The Raman Spectrum of Graphitic Carbon 4.2.2. The Silicon Raman Spectrum 5. The Cluster Tool at the Ion Beam Center 5.1. General Concept 5.2. Sputtering Chamber 5.3. The Environmental Chamber 5.4. The Analysis Chamber 5.5. The Ion Beam Analysis Chamber 5.5.1. The Experimental Setup 6. The Carbon Nickel System 6.1. Experimental Details 6.1.1. Film growth 6.1.2. Characterization 6.2. Results 6.3. Discussion 7. The Silicon Silver System 7.1. Experimental 7.1.1. Film Preparation 7.1.2. In Situ Raman Spectroscopy 7.1.3. In Situ Rutherford Backscattering Spectrometry 7.2. Results 7.2.1. Raman Spectroscopy 7.2.2. Rutherford Backscattering Spectrometry 7.2.3. X-ray Diffraction 7.2.4. Optical and Scanning Electron Microscopy 7.3. Discussion 8. Conclusion and Outlook A. Appendix A.1. Spectroscopic Lineshapes A.1.1. The Lorentzian Lineshape A.1.2. The Breit-Wigner-Fano Lineshape A.1.3. The Doniach-Sunjic Lineshape A.1.4. The Gaussian Lineshape A.1.5. The Voigt Lineshape A.2. Statistcial Distribution Functions A.2.1. The Gamma Distribution Bibliography

Die Arbeit beschäftigt sich mit der Erweiterung der für dicke Proben schon mit Erfolg eingesetzten Werkstoffanalytischen Methode Elektronenstrahl-Mikroanalyse (ESMA) mittels Peak/Untergrund-Verhältnissen auf die Analyse von dünnen Schichten (unter 1 μm) zur qualitative und quantitativen Elementanalyse sowie zur Ermittlung von Schichtdicken. Weiterhin wird auf der Basis von einer ESMA-Methode für zwei dünne Schichten auf einem Substrat wird ein Modell zur Ermittlung des Phasenwachstumskoeffizienten für eine intermetallische Phase die sich bei der Diffusion zwischen einer dünnen Schicht und einem Substrat bildet, mittels ESMA-Messungen bei gleichzeitiger Erwärmung der Probe dargestellt. / The paper deals with the application of the materials analysis method EPMA by peak-to-background ratios, which is currently being used for the analysis of thick samples successfully, to thin layers (less than 1 μm) for the quantitative element analysis as well as for thickness prediction. In addition a model has been established on the Basis of an EPMA method for two films on a substrate for deriving the phase growth coefficient of an inter-metallic phase which grows during the diffusion between a thin layer and a substrate from EPMA measurements while simultaneously heating the sample.