Les TCOs (Transparent Conductive Oxide) trouvent des applications dans de nombreux domaines s'étendant del'électrochromie au photovoltaique en passant par l'opto-électronique. Parmi les matériaux historiques, les TCOs detype n font l'objet d'une littérature abondante tandis que les TCO de type p sont quant à eux étudiés de façon plusconfidentielle mais commencent à susciter un engouement, notamment dans l'objectif de jonctions p-ntransparentes.Sur la base de la théorie de la méthode de modulation chimique de bande de valence, le composé CuCrO2 destructure délafossite est considéré comme un candidat intéressant de TCO de type p. L'objectif de ces travaux estd'élaborer des films minces à base de CuCrO2 avec une transmittance optique acceptable et une conductivitéélectrique de type p élevée afin de envisager la possibilité de fabrication des jonctions p-n transparents pourdiverses applications.Dans ce travail, les films CuCrO2 ont été déposés par co pulvérisation cathodique magnétron en condition réactiveà partir de cibles métalliques. Une substitution partielle de Cr par Mg a ensuite été effectuée et l'influence del'épaisseur du film CuCrO2 :Mg sur ses propriétés optoélectroniques a été étudiée. Enfin, des revêtementsd'architecture sandwich CuCrO2 :Mg/Ag/CuCrO2 :Mg ont été élaborés en faisant varier le temps de dépôt de lacouche intermédiaire d'argent afin d'améliorer les performances optoélectroniques des films. / Transparent conductive oxides (TCOs) can be widely used in various domains from electrochromics to photovoltaicsowing to their unique optoelectronic properties. During the history of the development of TCOs, most attention hasbeen focused on n-type TCOs, while p-type TCOs have made slow progress. Recently, the studies on p-type TCOsraised many interest especially due to their potential application in the fabrication of transparent p-n junctions.Based on the theory of chemical method of valance band, CuCrO2 compound with delafossite structure isconsidered as an interesting candidate for p-type TCOs. The objective of this work is to synthesize CuCrO2-basedthin films with acceptable optical transmittance and high p-type electrical conductivity in order to explore thepossibility of fabrication of transparent p-n junctions for various applications.In this work, CuCrO2 films were deposited by reactive sputtering from metallic targets. Then, partial Cr substitutionby Mg was performed into CuCrO2 films and the influence of the films thickness on its optoelectronic properties wasstudied. Finally, sandwich architectural coatings of CuCrO2 :Mg/Ag/CuCrO2 :Mg were designed in order to improvethe films optoelectronic performances.

<p>The technique of magnetron sputtering is considered for the deposition of silicon rich films. Attention was paid to the possibility to produce light emitting silicon rich films by three different methods, such as reactive magnetron sputtering, co-sputtering from silicon/silicon dioxide targets and a stacked film approach. It was found that photoluminescence of the films deposited in presence of hydrogen was much grater then that for other samples.</p> <p>A model of reactive sputter deposition was also developed and tested in this work. Results achieved in numerical simulation are compared with experimental data and show a good correlation.</p> <p>An experimental unit for magnetron sputtering was designed and built based on a sphere-shaped vacuum chamber equipped with a commercially available magnetron sputter gun, RF generator as power supply unit, vacuum controllers, mass flow controllers, in-situ thickness monitor, temperature controller and other supplemental equipment.</p> <p>Characterization of deposited film was made usmg Profile Measurement, ellipsometry, Rutherford Back Scattering measurements, X-Ray Diffraction measurements and photoluminescence measurements.</p> <p>The achieved results show the principal possibility of getting microcrystalline silicon films and light emitting silicon nanocrystals embedded into silicon dioxide matrix by the sputter deposition technique.</p> / Master of Science (MS)

<p>The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in VO2 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-VO2 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of VO2 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of VO2 thin films. A reversible thermal tunability of the optical/dielectric constants of VO2 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in VO2 host matrix.</p>

<p>The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in VO2 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-VO2 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of VO2 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of VO2 thin films. A reversible thermal tunability of the optical/dielectric constants of VO2 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in VO2 host matrix.</p>

Global warming and developments of alternative energy technologies have become important issues nowadays. Subsequently, the concept of energy harvesting is rising because of its ability of transferring waste energy into usable energy. Thermoelectric devices play a role in this field since there is tremendous waste heat existing in our lives, such as heat from engines, generators, stoves, computers, etc. Thermoelectric devices can extract the waste heat and turn them into electricity. Moreover, the reverse thermoelectric phenomenon has the function of cooling which can be applied to refrigerator or heat dissipation for electronic devices. However, the energy conversion efficiency is still low comparing to other energy technologies. The efficiency is judged by thermoelectric figure of merit (ZT), defined by Seebeck coefficient, electrical conductivity and thermal conductivity. In order to improve ZT, thin film materials are good candidates because of their structural effects on altering ZT.    Ca3Co4O9 thin films grown by reactive radio frequency magnetron sputtering followed by post-annealing process is studied in this thesis. Structural properties of the films with the evolution of elemental ratio (Ca/Co) of calcium and cobalt have been investigated. For the investigations, three samples having elemental ratio 0.82, 0.72, and 0.66 for sample CCO1, CCO2 and COO3, respectively, have been prepared. Structural properties of the films have been investigated by X-ray diffraction (XRD) θ-2θ and pole figure analyses. Surface morphology of the films has been investigated by scanning electron microscopic (SEM) analyses. The highly oriented and phase pure epitaxial Ca3Co4O9 thin films were obtained in the end.   Mixing of ScN and CrN to obtain ScxCr1-xN solid solution thin films by DC magnetron sputtering is the other task in this thesis. Growth of ScN and CrN thin films were studied first in order to get the best mixed growth conditions. The phase shifts between ScN (111) and CrN (111) peaks were observed in mixed growth films by XRD θ-2θ measurements, indicating the formation of ScxCr1-xN. Surface morphology of the films were investigated by SEM. The (111)-oriented ScxCr1-xN thin films with decent surface smoothness grown by DC magnetron sputtering at 600 °C in pure nitrogen with bias were developed.

Philosophiae Doctor - PhD / The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in VO2 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-VO2 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of VO2 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of VO2 thin films. A reversible thermal tunability of the optical/dielectric constants of VO2 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in VO2 host matrix. / South Africa

Magister Philosophiae - MPhil / The fascinating optical properties of metallic nanostructures, dominated by collective oscillations of free electrons known as plasmons, open new opportunities for the development of devices fabrication based on noble metal nanoparticle composite materials. This thesis demonstrates a low-cost and versatile technique to produce stimuli-responsive ultrafast plasmonic nanostructures with reversible tunable optical properties. Albeit challenging, further control using thermal external stimuli to tune the local environment of gold nanoparticles embedded in V02 host matrix would be ideal for the design of responsive functional nanocomposites. We prepared Au-V02 nanocomposite thin films by the inverted cylindrical reactive magnetron sputtering (ICMS) known as hollow cathode magnetron sputtering for the first time and report the reversible tuning of surface plasmon resonance of Au nanoparticles by only adjusting the external temperature stimuli. The structural, morphological, interfacial analysis and optical properties of the optimized nanostructures have been studied. ICMS has been attracting much attention for its enclosed geometry and its ability to deposit on large area, uniform coating of smart nanocomposites at high deposition rate. Before achieving the aforementioned goals, a systematic study and optimization process of V02 host matrix has been done by studying the influence of deposition parameters on the structural, morphological and optical switching properties of V02 thin films. A reversible thermal tunability of the optical/dielectric constants of V02 thin films by spectroscopic ellipsometry has been intensively also studied in order to bring more insights about the shift of the plasmon of gold nanoparticles imbedded in V02 host matrix.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Zr-Hf-N and Zr-Hf thin films were deposited by reactive magnetron sputtering in order to verify the influence of small hafnium contents that are present as contaminants on zirconium deposition targets. For this purpose different hafnium contents in the films were intentionally added by varying the deposition power. The samples were characterized by X-ray diffraction (XRD), dispersive energy X-ray spectroscopy (EDS), Rutherford backscattering spectroscopy (RBS) and nanohardness analyzes. The ZrHfN thin films were deposited and had a concentration of at% Hf of 0.49; 0.56; 0.80; 1.87 and 2.70. The deposited Zr-Hf alloys exhibited hafnium contents at up to 1.21%; 1.24; 4.35; 7.94 and 11.49. The crystalline phase obtained for the nitride films had a cubic face centered structure (FCC) and was not modified by the increase in hafnium content. The alloys presented amorphous with some crystalline regions of hexagonal structure. The hardness values ranged from 21.4 to 25.1 GPa for nitrides and from 6.1 to 8.4 GPa for zirconium alloys. / Filmes finos de Zr-Hf-N e Zr-Hf foram depositados por magnetron sputtering reativo com o intuito de verificar a influência de pequenos teores de háfnio que estão presentes como contaminantes nos alvos de deposição de zircônio. Para isto foram adicionados intencionalmente diferentes teores de háfnio nos filmes através da variação da potência de deposição. As amostras foram caracterizadas por difração de raios-X (DRX), espectroscopia de raios-Xpor energia dispersiva (EDS), espectroscopia por retroespalhamento Rutherford (RBS) e análises de nanodureza. Os filmes finos de ZrHfN foram depositados e apresentaram concentração em at.% de Hf de 0,49; 0,56; 0,80; 1,87 e 2,70. As ligas Zr-Hf depositadas apresentaram teores de háfnio em at.% de 1,21; 1,24; 4,35; 7,94 e 11,49. A fase cristalina obtida para os filmes os nitretos tinha estrutura cúbica de face centrada (CFC) e não foi modificada pelo aumento do teor de háfnio. As ligas se apresentaram amorfas com algumas regiões cristalinas de estrutura hexagonal. Os valores de dureza variaram de 21,4 a 25,1 GPa para os nitretos e de 6,1 a 8,4 GPa para as ligas de zircônio. / São Cristóvão, SE

Cette étude porte sur l’élaboration et la caractérisation des propriétés de revêtements de phases Magnéli de titane (TinO2n-1) en vue de leur application tribologique. Les dépôts ont été élaborés par pulvérisation cathodique magnétron en condition réactive à partir de cible métallique de titane dans une atmosphère O2/Ar sur un porte substrat rotatif chauffant.La première partie de l’étude appuie sur la synthèse de monocouches de phases Magnéli de titane. L’influence des principaux paramètres d’élaboration (débit d’oxygène, température du porte substrat) a été analysé au regard de la structure et de la morphologie des revêtements synthétisés. Ensuite, des bicouches TinO2n-1/AlTiN ont été synthétisées par la technique de pulvérisation cathodique magnétron et de l’arc électrique sous basse pression, respectivement. Cependant, la phase et l’épaisseur de la couche de surface d’oxyde de titane ainsi que l’épaisseur de la sous-couche AlTiN ont été choisies comme les paramètres à étudier.La deuxième partie concerne les propriétés mécaniques (nano dureté instrumenté, module d’élasticité, test Mercedes et scratch test) et tribologiques (test pion disque) des revêtements monocouches et bicouches. Une attention particulière a été portée à l’influence de la température du test de frottement sur le taux d’usure des revêtements duplex. / The present work deals with the synthesis and the structural, mechanical and tribological characterization of titanium Magnéli phases (TinO2n-1) coatings for tribological application. The thin films were prepared by reactive magnetron sputtering from titanium target in a reactive O2/Ar gas mixture using a rotating and heating substrate holder.The first part of the study is based on the synthesis of titanium Magneli phase monolayers. The influence of the main synthesis parameters (oxygen flow rate, temperature of the substrate holder) was analyzed in relation with the structure and the morphology of the synthesized coatings. Then TinO2n-1/AlTiN bilayers were synthesized by the reactive magnetron sputtering and the low pressure electric arc techniques, respectively. The phase and the thickness of the top layer of titanium oxide and the thickness of the under layer AlTiN were selected as the parameters to be studied.The second part concerns the mechanical properties (nano hardness instrumented, elasticity modulus, Mercedes test and scratch test) and tribological properties (pin on disc test) of the monolayer and bilayer coatings. Particular attention was paid to the influence of the friction test temperature on the bilayer coatings wear rates.

L’un des enjeux relatif au déploiement des piles à combustible à oxyde solide comme système de production d’une énergie propre relève de la température de fonctionnement qui est actuellement autour de 1000°C. Abaisser cette température tout en préservant les performances afin de réduire les coûts de fabrication et d’augmenter la durée de vie des systèmes a été l’objectif dece travail de doctorat.Un coeur de pile à combustible (anode-électrolyte-cathode) élaboré avec des procédés physiques de dépôts (projection par plasma atmosphérique et pulvérisation cathodique magnétron) a été développé et optimisé sur un support métallique poreux. Les matériaux étudiés ont été un cermet en Nickel-Zircone stabilisée à l’Ytttrium (Ni-YSZ) pour l’anode, un électrolyte en YSZ avec ou sans couche de cérine gadoliniée (GDC) et les nickelates de terres rares comme cathode. La maitrise des procédés de revêtements a permis de réduire les épaisseurs de chaque couche et d’assurer la cohésion de l’ensemble des 3 couches avec des caractéristiques cristallographiques, microstructurales et de porosité adaptées. . Les performances électrochimiques ont été étudiées pour chaque élément du coeur de pile puis pour l’ensemble du système élaboré sur métal poreux. Même si les performances atteintes ne sont pas encore suffisantes, les procédés de revêtements optimisés pour recouvrir un support métallique poreux ont confirmé leur potentiel. / Energy production by a clean and environmental processes is a real challenge. Fuel cell technology is good candidate to answer this objective. The major problem of the Solid Oxide Fuel Cell is their high operating temperature (around 1000°C) for a massive industrialisation. Decreasing these temperature at 700°C allows a reduction of cost manufacturing and increase the lifetime, in this case the new challenge is to avoid the performances losses.During this phD work, dry surface treatment processes are employed for produce the fuel cell core. The thickness reduction of each part limit the performances decreasing generate by the modification of the temperature. The materials used is a Ni-Yttria stabilised zirconia cermet (Ni-YSZ) for the anode, YSZ with or without gadolinnia doped ceria (GDC) for electrolyte and rare earth nickelate for the cathode component. All material are a usual employed in the SOFC technology. All coating are synthesized and characterised separately. After a third generation of fuel cell is realized on ITM porous metal support produced by PLANSEE. The anode has been deposit by atmospheric plasma spray, the electrolyte and cathode have been synthesised by reactive magnetron sputtering.