Pour résoudre la limitation inhérente au procédé d’impression laser LIFT, une approche utilisant une double impulsion (DP-LIFT) a été développée au cours de cette thèse. Dans ce processus, une irradiation laser de durée de quelques dizaines de microsecondes crée un bain de métal en fusion et une seconde impulsion ultra-brève induit le mouvement du fluide, la formation d’un jet ou d’une goutte et le transfert du métal liquide. Cette thèse présente une étude expérimentale détaillée sur le processus DP-LIFT. L'influence des paramètres des deux irradiations laser a été étudiée en s’appyuant sur un ensemble de méthodes d'observation. Pour étudier l’influence de ces paramètres sur la dynamique de l’éjection, un modèle basé sur la conservation de l’énergie a été utilisé. De plus, nous avons démontré que, pour certaines configurations des diamètres respectifs des deux spots lasers, des nanojets focalisés étaient générés. Enfin, en conservant une épaisseur fixe du film métallique, des gouttelettes uniques, sans débris, d'un diamètre allant de 670 nm à 6,0 µm ont été imprimées avec une reproductibilité élevée. des matrices de piliers ont également été imprimées pour démontrer le potentiel de la méthode LIFT à double impulsion pour la fabrication de micro-structures 3D / To solve the inherent limitation of Laser-induced Forward Transfer (LIFT), a double pulse LIFT (DP-LIFT) approach has been developed in this thesis. In this process, a first long pulse laser irradiation creates a melted metal pool and a second ultrashort pulse induces the fluid motion and initiates the jetting transfer. This thesis provides a detailed experimental study on the DP-LIFT process. The influence of double pulse parameters on the jetting phenomena has been carefully studied by means of various observation methods. To predict the jetting behaviors, an energy balanced model has been used. Moreover, we demonstrated that for some configurations of the respective diameters of the two lasers, focused nanojets are generated from the melting pool. Finally, from a fixed thickness of the donor film, debris-free single droplets with diameters ranging from 670 nm to 6.0 µm have been printed with high reproducibility. 2.5 D pillars matrix are printed to demonstrate the potential of the double pulse LIFT method for the fabrication of 3D micro-structures.

Les travaux de cette thèse ont porté sur la conception et la réalisation d'un dispositif d'éclairage surfacique à géométrie planaire à base de structures plasmoniques, pour un fonctionnement à 633nm. Ce dispositif sera capable de convertir une lumière incidente cohérente en un faisceau de sortie uniforme sur la surface du dispositif, collimaté et avec un angle prédéfini par rapport au plan du dispositif. Pour réaliser ce dispositif, la solution envisagée est l'utilisation d'un réseau de guides d'onde diélectriques pour répartir la lumière sur la surface, et de chaînes de nano-structures d'argent couplées aux guides, dimensionnées comme des antennes pour réémettre la lumière hors du plan.Les travaux réalisés ont mis en évidence le contrôle du couplage entre le guide d'onde et la chaine de nano-structures d'argent, modulable par plusieurs paramètres dans une gamme comprise entre 10% et 90 % : nombre de particules, dimensions des particules, distance entre le guide et les particules. En jouant sur la période de la chaine, il est possible d'obtenir un rayonnement hors-plan, avec un angle déterminé par la formule des réseaux de diffraction. Des émetteurs élémentaires, composés d’un guide et de chaines de particules, ont été fabriquées en salle blanche et caractérisés sur un banc d’optique guidée à l'aide d'un montage de projection dans le plan de Fourier. Les diagrammes de rayonnement expérimentaux sont en accord avec les simulations. De premiers résultats ont également confirmé expérimentalement la possibilité de moduler le couplage guide-chaine en modifiant les dimensions des particules. Enfin le réseau de guides d'onde a été dimensionné pour une surface d'1 cm² et fabriqué en lithographie par projection. Les pertes linéiques mesurées dans les guides d'onde sont de l'ordre de 5 dB/mm. Plusieurs optimisations peuvent être réalisées pour améliorer la qualité des guides. A partir des données expérimentales obtenues et des simulations de propagation de faisceau, une configuration réaliste de dispositif d’éclairage incluant le nombre et le positionnement des émetteurs sur le réseau de guides a été proposée. L’ensemble des travaux réalisés valident l’approche choisie. / This work has focused on the design and realization of a planar lighting device based on plasmonic structures, for a 633nm operation. This device will be able to convert a coherent incident light into a uniform output beam over the surface of the device, collimated and with a predefined angle with respect to the plane of the device. To achieve this feature, the proposed solution is the use of an array of dielectric waveguides to distribute the light over the surface, and silver nanostructures chains coupled to the waveguides and dimensioned as antennas to retransmit the light out of the plane. The work carried out has highlighted the control of the coupling between the waveguide and the silver nanostructures chain, modulated by several parameters in a range between 10% and 90%: the number of particles, particle size, distance between the guide and the particles. By playing on the period of the chain, it is possible to obtain an out-of-plane radiation, with an angle determined by the diffraction gratings formula. Elementary emitters, consisting of a guide and particle chains, were manufactured in a clean room and characterized on a guided wave optical bench with Fourier plane projection set-up. The experimental radiation patterns are in agreement with the simulations one. First results have also experimentally confirmed the possibility of modulating the waveguide-chain coupling by modifying the dimensions of the particles. Finally, the waveguide network has been dimensioned for an 1 cm² surface and manufactured with projection lithography. The linear losses measured in the waveguides are of the order of 5 dB / mm. Several optimizations can be made to improve the quality of the guides. From the experimental data obtained and the beam propagation simulations, a realistic configuration of the lighting device including the number and positioning of the transmitters on the waveguide network has been proposed. All the works carried out validate the chosen approach.

The Terahertz region of the electromagnetic spectrum is the region between microwaves and infra-red, dubbed the terahertz 'gap' due to its relative underdevelopment in terms of technology. This region is marked by expensive and inconvenient sources that are bulky or that require cryogenic cooling for normal operation, therefore creating a need for cheap and easy to use terahertz sources. Carbon nanotubes have received considerable attention since their discovery due to their unique physical and electronic properties. Many applications have been proposed using especially Single-Walled Carbon Nanotubes (SWCNTs), and a number of commercial technologies exist. In this work, we have proposed to use SWCNTs as the basis for a cheap, compact and room temperature-operating Terahertz source. We have characterized the SWCNT source, and we present results on transport characteristics (I–V curves), radiation patterns, spectra, polarization as well as optical, SEM and AFM imaging. We show that the radiation spectrum is vi determined by integrated antennas coupled to the SWCNTs, and preliminary power calibration indicates that the radiated power exceeds the power predicated by the Nyquist formula.

Electrodeposition is one of the main techniques for fabricating conductive parts with one or two dimensions in the micron size range. This technique is utilized to coat surfaces with protective films of several micrometers thickness or fabricate standalone microstructures. In this process, an electrochemical reaction occurs on the electrode surface by applying an electric voltage, called overpotential. Different electrochemical practices were presented in the literature to obtain kinetic parameters of an electrochemical reaction but most of these practices are hard to implement for the reactions occur on a microelectrode. Toward addressing this issue, the first part of the dissertation work presents a combined experimental and analytical method which can more appropriately provides for the kinetic measurement on a microelectrode. Another issue which occurs for electrodeposition on microscale recessed areas is the deviation of the profile of the deposition front from the substrate shape. Non-uniform deposition front usually obtains for a deposit evolved from a flat substrate with microscale size. Consequently, a subsequent precision grinding process is required to level the surface of the electrodeposited microparts. In order to remove the need for this subsequent process, in the second and third parts of the dissertation work, multiphysics modeling was used to study the effects of the fabrication parameters on the uniformity of the deposit surface and suggest a design strategy. Surface texture of the deposit is another parameter which depends on the fabrication parameters. Several important characteristics of the electrodeposited coating including its wettability depend on the surface texture. The next part of the dissertation work presents an experimental investigation and a theoretical explanation for the effects of the overpotential and bath concentration on the surface texture of the copper deposit. As a result of this investigation, a novel two-step electrodeposition technique is developed to fabricate a superhydrophobic copper coating. In the last part of the dissertation work, similar investigation to the previous sections was presented for the effects of the fabrication parameters on the crystalline structure of the deposit. This investigation shows that nanocrystalline and superplastic materials can be fabricated by electrodeposition if appropriate fabrication parameters are applied. / Ph. D.

In this thesis, intrinsic Josephson junctions, naturally formed in the strongly anisotropic high-temperature superconductor Bi2Sr2CaCu2O8 (Bi-2212), are studied experimentally. For this purpose, small mesa structures are fabricated on the surface of single crystals using micro- and nano-fabrication tools, focused ion beam is used to reduce the area of the mesa-structures down to ≈ 1 × 1 μm2. The properties of charge transport across copper-oxide layers inside the mesas are studied by intrinsic tunneling spectroscopy. Temperature, bias and magnetic field dependences of current-voltage characteristics are examined. In the main part of the thesis, the behavior of intrinsic Josephson junctions in magnetic fields B parallel to the copper-oxide planes is studied. Parallel magnetic fields penetrate the junctions in the form of Josephson vortices (fluxons). At high magnetic fields, fluxons are arranged in a regular lattice and are accelerated by a sufficient high transport current. As the fluxon lattice is moving through the mesa, it emits electromagnetic waves in the important THz frequency range. Properties of Bi-2212 mesas in this flux-flow regime are studied in this thesis. The following new observations were made during the course of this work: a crossover from thermal activation above Tc to quantum tunneling below Tc is seen in the interlayer transport-mechanism, the Fraunhofer pattern of Ic(B) is observed clearly in Bi-2212, superluminal electromagnetic cavity resonances and phonon-polaritons are observed in Bi-2212. It is argued that the employed technique for miniaturization of mesas and the obtained results can be useful for a better understanding of fundamental properties of high-temperature superconductors and for the realizations of coherent flux-flow oscillators and coherent phonon-polariton generators in the important THz frequency range. / At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 6: Manuscript.

In this thesis, the tunneling between individual atomic layers in structures of Bi2Sr2CaCu2O8+x based high-temperature superconductors are experimentally studied employing the intrinsic Josephson effect. A special attention is paid to the fabrication of small mesa structures using micro and nanofabrication techniques. In the first part of the thesis, the periodic Fraunhofer-like modulation of the critical current of the junctions as a function of in-plane magnetic field is investigated. A transition from a modulation with a half flux quantum to a flux quantum periodicity is demonstrated with increasing field and decreasing junction length. It is interpreted in terms of the transformation of the static fluxon lattice of stacked, strongly coupled intrinsic Josephson junctions and compared with theoretical predictions. A fluxon phase diagram is constructed.Numerical simulations have been carried out to complement the experimental data. In the second part of the thesis, different resonant phenomena are studied in the dynamic flux-flow state at high magnetic fields, including Eck-resonances and Fiske steps. Different resonant modes and their velocities, including superluminal modes, are identified. In the third part, different experiments attempting to detect radiation from small mesa structures using different setups based on hot-electron bolometer mixers and calorimeters are described. No distinct radiation with emission powers higher than about 500pW could be detected. Furthermore, the interaction with external GHz-radiation is studied. Resonances attributed to an induced flux-flow are observed, and the reflectivity of the sample can be tuned by switching mesas between the superconducting and quasiparticle state. In the last part, the resistive switching of mesas at high bias is studied. It is attributed to a persistent electrical doping of the crystal. Superconducting properties such as the critical current and temperature and the tunneling spectra are analyzed at different doping states of the same sample. The dynamics of the doping is studied, and attributed to two mechanisms; a charge-transfer effect and oxygen reordering

Le champ d'application des microsystèmes n'a cessé de s'élargir pendant les quinze dernières années en particulier vers la communication ou vers les biotechnologies. Pour augmenter les fonctionnalités des microsystèmes, l'utilisation de nano-objets semble devenir une voie incontournable, mais qui butte souvent sur des problèmes mes de manipulation spatiale visant à les intégrer dans une architecture fonctionnelle. Pour résoudre ces problèmes d'intégration, l'utilisation de phénomènes d'assemblage dirigé, c'est à dire des phénomènes physiques permettant de manipuler collectivement des nano-objets semble très prometteuse. Dans ce contexte, l'objectif de notre thèse a été de concevoir des outils fluidiques innovants capables de réaliser des opérations de manipulation spatiale ou conformationnelle de nano-objets ou de molécules. Il s'agit d'une recherche pluridisciplinaire à la frontière entre la micro- et nano-fabrication, la micro- et nano-fluidique, la biologie moléculaire, l'imagerie de molécules individuelles, et la biophysique. La thèse est composée de deux projets assez indépendants : une étude de nanofluidique pour le contrôle conformationnel de chromosomes issus de cellules vivantes, et un travail de microfluidique sur un phénomène d'assemblage spontané sur gel hydrophile. Dans un premier temps, nous décrivons un procédé de fabrication d'hydrogels structurés, et nous montrons que ces hydrogels constituent un support efficace pour organiser spatialement des nano-objets. Ce phénomène d'organisation est spontané, et il se produit lors du séchage du liquide. Nous avons donc voulu comprendre les mécanismes fluidiques ayant lieu au cours du séchage en utilisant des traceurs fluorescents. Nous identifions plusieurs phénomènes expliquant les phénomènes d'organisation spatiale de particules, et nous proposons des applications pour ce procédé innovant. Grâce aux dispositifs nanofluidiques que nous avons fabriqués, nous menons des expériences de manipula tion de molécules d'ADN individuelles en milieu confiné. Nous analysons le comportement de l'ADN - son élongation, sa mobilité, l'effet de la salinité, le rôle du matériau dans lesquels le nanocanaux sont inscrits - en utilisant deux modes d'actionnement, à savoir l'électrophorèse et l'hydrodynamique, et nous montrons, pour la première fois, l'intérêt de l'hydrodynamique pour la manipulation d'ADN dans des nanostructures. Nous proposons enfin quelques applications pour ce procédé de manipulation d'ADN innovant.