In a conventional nonvolatile memory, charge is stored in a polysilicon floating gate (FG) surrounded by dielectrics. The scaling limitation stems from the requirement of very thin tunnel oxide layer. For FG, once the tunnel oxide develops a leaky path under repeated write/erase operation, all the stored charge will be lost.Therefore, the thickness of the tunnel oxide can not be scaled down to about 7 nm. To alleviate the scaling limitation of the conventional FG device while preserving the fundamental operating principle of the memory, we have studied the distributed charge storage approach such as the nanocrystal nonvolatile memory. Each nanodot will typically store only a handful of electrons; collectively the charges stored in these dots control the channel conductivity of the memory device. Nanocrystal charge storage offers several advantages, the main one being the potential to use thinner tunnel oxide without sacrificing non-volatility. This is a quite attractive proposition since reducing the tunnel oxide thickness is a key to lowering operating voltages and/or increasing operating speeds. The improved scalability results not only from the distributed nature of the charge storage, which makes the storage more robust and fault-tolerant, but also from the beneficial effects of Coulomb blockade. A local leaky path will not cause a fatal loss of information for the nanocrystal non-volatile memory device. Also, the nanocrystal memory device can maintain good retention characteristics and lower the power consumption. In recent years, nonvolatile memory with nanocrystals cell have widely applied to overcome the issue of operation and reliability for conventional floating gate memory. The excellent electrical characteristics of memory device need good endurance, long retention time and small operation voltage. Among numerous memory devices with nanocrystals, the memory device with metal nanocrystals was widely researched. It will be a new candidate for flash memory. The advantages of metal nanocrystals has have higher density of states around Fermi level, stronger coupling with conduction channel, wide range of available work functions and smaller energy perturbation due to carrier confinement. So metal nanocrystals can reduce operate voltage, and increase write/erase speed and endurance. Most important of all, we can control the sizes of nanocrystals dot and manufacture at low temperature¡CThis advantage can apply to thin film transistor liquid crystal display; it fabricates driving IC and logical IC on panel for diverseness and adds memory beside switch TFT as image storage to reduce power consumption for portability. In this thesis, we will discuss metal nanocrystals as memory storage medium. And we can use high temperature oxidation, low temperature annealing with oxygen to form nanocrystals. Most importantly, we analyze the effect of electron storage at metal nanocrystals by means of material and electrical analysis.

In this study, we develop self-assembled nano-metal-dots etching mask techniques to fabricate quantum dots (QDs) nano-pillars. We explain the self-assembled nano-metal-dots formation processes by using Dewetting model. Two important experimental factors including (1) interaction force between film and vapor during annealing (£^FV),¡]2¡^interaction force between film and substrate (£^FS) are study to investigate the self-assembled processes. A 200nm thick SiO2 buffer layer is first deposited on the GaAs substrate to congregate thermal energy during the RTA process. In our group, the QDs optimum grown temperature condition is 570¢J, so we develop Au-Ge nano-dots process especially for GaAs based QDs samples. The 8nm thick Au-Ge is annealed at lower 500oC for 60sec under the pressure of 5 E6 Torr to format the nano-dots on QDs samples. The Au-Ge nano-dots have a size and density of 250 ¡Ó 50 nm and 4 E8 cm-2,respectively. We use the Au-Ge nano-dots as mask and dry etching process to fabricate the 9-layer vertical coupled QDs nano-pillars. The diameter and height of the QDs nano-pillar are 250, and 800nm, respectively. According to the QDs density, each nano-pillar contains 1600 QDs in it. The QDs nano-pillar resonance signals are observed by the low temperature cryogenic cathode-luminescence measurement. A strong nano-pillar resonance signal in 1050 nm matched to our simulation results is observed.

Dans le premier chapitre de cette thèse, nous introduisons le concept de nanodot organique (OND) comme une alternative aux quantum dots (QDs). Ces nano émetteurs «tout organique» sont préparés par synthèse bottom-up et contrôle,à l’échelle du nanoobjet, de la réponse optique par confinement du chromophore au sein d’une structure dendritique. Ceci conduit à des nanoobjets présentant une brillance exceptionnelle à un ou deux photons en faisant des composés d’intérêt majeur pour l’imagerie in vivo. Le deuxième chapitre décrit la synthèse et la caractérisation de la première famille d’OND hydrophiles. Deux types d’absorbeurs à deux photons ont été sélectionnés car présentant des propriétés optiques et des structures différentes. Ensuite, l’hydro solubilité a été assurée par l’accrochage de groupes H2N(CH2)2NEt2 à la périphérie. Dans les chapitres 3 et 4, nous proposons une alternative aux OND cationiques par greffage de chaîne polyéthylèneglycol à la périphérie. Ceci améliore la solubilité et la biocompatibilité. Un OND hydrosoluble bimodal pouvant être utilisé en IRM du19Fet imagerie de fluorescence est également préparé. Dans ce chapitre l’étude par RMN et par imagerie confocale de trois dendrimères à cœur cyclophosphazène est également décrite. Finalement, le chapitre 5 décrit la préparation de systèmes synergique agissant en tandem pour la photo libération d’un substrat «en cage». Nous avons démontré qu’en combinant une antenne collectrice avec des unités encagées,il est possible d’obtenir une libération efficace de molécules actives. Par ingénierie moléculaire nous avons préparé trois systèmes synergiques différents: (i) Une triade symétrique basée sur un chromophore portant des chaîne hydrophile TEG et connecté à unités PPG encageant une unité glutamate (ii) Une dyade comportant un chromophore et une unité PPG au sein d’une architecture phosphorée, finalement (iii) une unité dendritique portant une unité encageante et 5 absorbeurs à deux photons / In the first chapter of this dissertation, we introduce the concept of organic nanodot (OND) as an alternative to quantum dots (QDs).These purely organic nanoemitters are obtained from a rational and bottom-up route based on the control, at the single nano-object level, of the optical responses via the covalent confinement of optimized chromophores within dendrimericarchitectures. This led to tuneable nano-objects which show record one-and two-photon brightness and have been shown to be a major interest for in vivoimaging.The second chapter describes the synthesis and structural characterization of the first family of ONDwith hydrophilic properties. Two different 2P absorber modules were selected for this aim, displaying different structural and optical properties. Then, the water solubility will be ensured by linking H2N(CH2)2NEt2.at the periphery. In Chapter 3and 4we propose an alternative to the cationic ONDs by replacing the external layer, with polyethylene glycol (neutral). This synthetic approach favorsthe hydrosolubility, and the compatibility in biological environment. Awater-soluble organic nanodot-based probethat could be used for both 19F MRI and optical fluorescence imagingis alsoprepared. In the same chapter, confocal imaging and NMR studies of three types of dendrimers with a cyclotriphosphazene core are described.Finally, the aim of chapter 5is the synthesis of synergic systems acting in tandem for the photorelease of a caged substrate. We demonstrate that combining a light harvesting antenna group with uncaging subunits leads to the efficient release of active molecules. Molecular engineering allowed us to prepare three different synergic systems, (i) a symmetrical tandem triad structure, based on one chromophore bearing hydrophilic TEG chains, which is directly connected to two PPG units caging one molecule of glutamate respectively, (ii) a dyad system bearing one chromophore and one PPG in phosphorus scaffold, finally (iii) a dendritic scaffold bearing 6 available position that was coated both with one equivalent ofuncaging moietyand the remaining positions with 2P absorbing modules.

In this thesis, we use self-assembled nano metal particles as a dry etching mask to from nanopillars. The nanopillars integrated with traditional light-emitting diode (LED) p-type GaN surface is designed to increase the light extraction efficiency. The initial fabrication process adopted in this study is using 100nm SiO2 as thermal aggregation layer. The poor thermal conductivity of SiO2 material will help to accumulate heat on the surface. Then, 10nm Ni thin film is deposited on the SiO2, and rapid annealed at 900oC (working pressure of 1~3¡Ñ10-6 Torr). The Ni nanospheres are prepared to integrate with LED chip processes. We use the etching times (pillar heights) as experimental parameters to study the degree of light extraction efficiency. Traditional right angle branch electrode samples of as grown, 20, 30, 40 sec etching time are analyzed by LI curve measurement. Under 20mA injection current, samples with 20, 30, 40 sec etching times have better light extraction than as grown, an increase of 6.54%, 3.27%, 1.63%, respectively. The experimental results reveal that self-assembled nano metal particles as a dry etching mask on the p-type GaN LED surface can increase the light extraction efficiency.

In this thesis, we study a series of Si-doped GaN thin films and nanodots. These samples are growth on c-face sapphire substrate by Molecular Beam Epitaxy. In Si-doped GaN thin film growth, different Si cell temperature are used to control the dopant concentration. Van der Pauw hall measurement is used to measure the carrier concentrations and the mobilities. As increase Si cell temperature, the carrier concentration and the mobility increase. The maximum carrier concentration is 8 ¡Ñ 1019 cm-3, and the maximum mobility is 194 cm2/V-s. As increasing the Si dopant concentration, the near band edge photoluminescence emission peak intensity increases, but the full width at half maximum broaden from 47 meV to 117 meV. In Raman measurement result, with the increasing of Si dopant concentration, the E2(high) mode shifts from 569.4 cm-1 to 567.9 cm-1. The A1(LO) mode disappears gradually. In the nanodot growth, the AFM images show that the nanodots size become large as increasing the growth time. The nanodots size is change from 1.2 nm to 5.6 nm high and 40 nm to 110 nm wide, but the density of the nanodots decreases from 1.9 ¡Ñ 1010 cm-2 to 6 ¡Ñ 109 cm-2 at 15 sec and 90 sec growth, respectively. According to the AFM image of the nanodots surface morphology, the nanodots growth mode should be the Stranski-Krastanow mode.

The relatively recent discovery of the giant electrocaloric effect in ferroelectric ceramics may lead to new solid state cooling technologies that are energy efficient, reliable, portable, and environmentally friendly. This phenomenon, along with many other novel field-coupled properties of ferroelectrics, such as piezoelectricity, pyroelectricity, the electro-optic effect, phase changes, and polarization switching, make these materials useful for a wide range of technological applications including sensors, ultrasound, infrared cameras, sonar, diesel engine fuel injectors, ferroelectric random access memory, electro-optic modulators, vibration control, and electrocaloric cooling devices. Most of world’s current cooling and refrigeration technology is based upon the vapor-compression cycle of a refrigerant. Refrigeration systems that are based on this technology are bulky, require moving parts in the compressor and some of them have a less than optimal environmental impact. Thin film devices that utilize the electrocaloric effect could have a significant impact on refrigeration, heat pumps, air conditioning, energy scavenging, and computer cooling systems. Especially for the latter ones, the fan-based solutions are not likely to be able to keep up with the increases in computing power and the resulting current densities in integrated circuits. The ability to make quantitative predictions of the behavior of ferroelectric structures is of significant importance given the experimental efforts on the synthesis of barium titanate nanodots, nanorods, nanowires, and nanotubes, and lead zirconate titanate (PZT) thin films, and nanoparticles, and the potential for technological applications of these structures. The research contained herein implements a full thermo-electro-mechanical continuum framework and numerical methods based on phase-field modeling to study the domain and phase structure evolution associated with the electrocaloric effect in barium titanate ferroelectric nanodots. / text

Cette thèse vise à développer de nouveaux matériaux hybrides pour les applications en électrochimiluminescence. Les propriétés électrochimiluminescentes de nouveaux complexes de Pt(II) et d’Ir(III) ont été explorés comme alternative aux marqueurs existants. En plus, la combinaison de complexes et de carbon nanodots portant des groupes primaires ou tertiaires à la surface comme espèces coréactives a abouti à une stratégie intéressante pour éliminer la TPrA. Les carbon nanodots dans un systéme lié par liaison covantent avec complexes métalliques sont non seulement un support innocent pour les espèces actives d’ECL, mais agissent également comme coréactif, se révélant être une plateforme auto-améliorante en ECL. Enfin, un véritable immunoessai pour la détection des marqueurs cardiaques a été mis au point avec une sensibilité et une stabilité accrues pour les applications de détection biologique et biomédicale. La même technologie peut alors être appliquée à une variété d’autres analytes, ouvrant ainsi le site à d’autres dosages. / This doctoral dissertation aim to develop new hybrid materials for ECL applications. In the field of metal complexes, the electrochemiluminescent properties of new Pt(II) and Ir(III) complexes were investigated as alternative of existing complexes. Passing to nanomaterials, the combination of labels and NCNDs bearing primary or tertiary groups on the surface as alternative co-reactant species resulted an interesting strategy to eliminate the toxic TPrA. In particular, NCNDs in covalently linked system with metal complexes is not only an innocent carrier for ECL active species, but act also as co-reactant in the ECL process, revealing itself an ECL self-enhancing platform. Finally, a real immunoassay for cardiac marker detection has been built with enhanced sensitivity and stability, which is of fundamental importance for biological and bio-medical detection applications. The same technology can be applied to a variety of other analytes opening the venue to other assays.

L'industrie de la microélectronique est en perpétuelle évolution, surtout concernant la diminution des dimensions des composants. Ainsi, pour les nouvelles générations de mémoires non volatiles Flash, le poly-silicium de la grille flottante pourrait être remplacé par des nanoplots discrets de silicium. L'élaboration de ces nanoplots par LPCVD (Low Pressure Chemical Vapor Deposition) à partir de silane SiH4 sur un substrat amorphe SiO2 demeure l'une des voies privilégiées par l'industrie. Le fonctionnement de ce type de mémoires est fortement dépendant des conditions de synthèse des nanoplots de silicium. Ce travail de cette thèse visait donc à améliorer la compréhension des mécanismes de nucléation et de croissance en jeu. Nous avons étudié les premiers instants de la nucléation en chimie quantique, grâce à l'utilisation de la théorie DFT, en considérant l'oxyde de silicium comme surface de dépôt. Des lois cinétiques intrinsèques ont été tirées de ces résultats DFT et elles ont été implémentées dans un modèle de simulation à l'échelle du procédé industriel, sur la base du code de CFD Fluent. Pour la nucléation, il est apparu que seul le silylène, SiH2, peut se chimisorber à la surface du substrat. De plus, sa faible concentration et la première désorption de H2, qui est très lente, expliquent le temps d'incubation. Pour la croissance, le caractère auto-catalytique des dépôts a été expliqué par la contribution très forte du silane au dépôt dès la seconde chimisorption. L'étape limitant la croissance est clairement la désorption de H2. La réalisation d'essais expérimentaux et la comparaison avec le modèle multi-échelles issu de notre travail a permis d'expliquer pourquoi les cinétiques classiques de la littérature surestiment la vitesse de dépôt des nanoplots. Il est aussi apparu que la vitesse de dépôt du silicium sur des nanoplots en croissance est plus forte que celle d'un film de silicium continu « épais ». La prise en compte des sites de chimisorption lors des premiers instants et la description détaillée de la désorption de H2 sont des paramètres clés pour rendre compte du comportement des dépôts de nanoplots de silicium. / The need of high integrated systems of the everyday life involves a permanent evolution of the microelectronic industry. Integrated circuits involving non volatile Flash memories are good examples of these trends. In this technology, the poly-silicon floating gate could be replaced by a discrete trap floating gate in which discrete traps are made up of silicon nanodots. The synthesis of nanodots by LPCVD (Low Pressure Chemical Vapor Deposition) from silane SiH4 on SiO2 surfaces remains one of the most promising ways of industrial synthesis. Despite a huge experimental effort, fundamental understanding of the key mechanisms of nanodots nucleation and growth remains elusive. Here we find the main objectives of the thesis. For nucleation, our main results reveal that only silylene SiH2 is involved in the very first steps of nucleation. The incubation time experimentally observed can be explained by the low SiH2 concentration and the first slow H2 desorption process. For growth, silane is the main responsible for deposition, which explains the autocatalytic behaviour of silicon deposition. The growth limiting step is clearly the H2 desorption process. Comparisons between experimental and multiscale modelling allow to explain why classical kinetics of the literature overestimate nanodots deposition rate. We have found that the silicon deposition rate is higher on nanometer silicon dots than on a continuous silicon film. Key parameters to conveniently model nanodots deposition are good descriptions of the first chemisorption sites and of the H2 desorption process.

Nanostructures were formed on diced specimens of several silicon carbide polytypes and silicon using electron beam lithography. A general introduction to nanostructure synthesis and electron beam lithography,are presented. A scanning electron microscope was retrofitted with a commercially available electron beam lithography package and an electrostatic beam blanker to permit nanoscale lithography to be performed. A process was first developed and optimized on silicon substrates to expose, poly-methyl-methacrylate (PMMA) resist with an electron beam to make nanoscale nickel masks for reactive ion etching. The masks consist of an array of nickel dots that range in size from 20 to 100 nm in diameter. Several nanoscale structures were then fabricated in silicon carbide using electron beam lithography. The structures produced are characterized by field emission Scanning Electron Microscopy.

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.