The development of new materials with novel properties plays an important role in improving our lives and welfare. Research in Nanotechnology can provide e.g. cheaper and smarter materials in applications such as energy storage and sensors. In order for this development to proceed, we need to be able to characterize the material properties at the nano-, and even the atomic scale. The ultimate goal is to be able to tailor them according to our needs. One of the great challenges concerning the characterization of nano-sized objects is how to achieve the physical contact to them. This thesis is focused on the contacting of nanoobjects with the aim of electrically characterizing them and subsequently understanding their electrical properties. The analyzed nanoobjects are carbon nanosheets, nanotetrapods, nanoparticles and molecular systems. Two contacting strategies were employed in this thesis. The first strategy involved the development of a focused ion beam (FIB) based nanocontact platform. The platform consists of gold nanoelectrodes, having nanogaps of 10-30 nm, on top of an insulating substrate. Gold nanoparticles, double-stranded DNA and cadmium telluride nanotetrapods have been trapped in the gaps by using dielectrophoresis. In certain studies, the gold electrodes have also been coated with conducting or non-conducting molecules, prior to the trapping of gold nanoparticles, in order to form molecular junctions. These junctions were subsequently electrically characterized to evaluate the conduction properties of these molecular systems. For the purpose of better controlling the attachment of molecules to the nanoelectrodes, a novel route to synthesize alkanedithiol coated gold nanoparticles was developed. The second contacting strategy was based on the versatility of the FIB instrument as a platform for in-situ manipulation and electrical characterization of non-functionalized and functionalized carbon nanosheets, where it was found that the functionalized samples had an increased conductivity by more than one order of magnitude. Both contacting strategies proved to be valuable for building knowledge around contacting and electrical characterization of nanoobjects

This dissertation aims to advance the current state of use of silicon atomic force microscope (AFM) cantilevers with integrated heaters. To this end, the research consists of two primary thrusts - demonstrating new applications for the cantilevers, and advancing the current state of understanding of their thermal and mechanical behavior to enable further applications. Among new applications, two are described. In the first application, the cantilevers are used for nanoscale material deposition, using heat to modulate the delivery of material from the nanoscale tip. In the second application, the cantilever performs thermal analysis with nanoscale spatial resolution, enabling thermal characterization of near surface and composite interphase regions that cannot be measured with bulk analysis techniques. The second thrust of the research seeks to address fundamental questions concerning the precision use of heated cantilevers. Efforts to this end include characterizing the mechanical, electrical, and thermal behavior of the cantilevers, and optimizing calibration methodology. A technique is developed for calibrating the cantilever spring constant while operating at elevated temperature. Finally, an analytical model is developed for the heat flow in the cantilever tip and relevant dimensionless numbers that govern the relative importance of the various components of the thermal environment are identified. The dimensionless numbers permit exploration of the sensitivity of the tip-substrate interface temperature to the environmental conditions.

The considerable interest in nanomaterials and nanotechnology over the last decade is attributed to Industry's desire for lower cost, more sophisticated devices and the opportunity that nanotechnology presents for scientists to explore the fundamental properties of nature at near atomic levels. In pursuit of these goals, researchers around the world have worked to both perfect existing technologies and also develop new nano-fabrication methods; however, no technique exists that is capable of producing complex, 2D and 3D nano-sized features of arbitrary shape, with smooth walls, and at low cost. This in part is due to two important limitations of current nanofabrication methods. First, 3D geometry is difficult if not impossible to fabricate, often requiring multiple lithography steps that are both expensive and do not scale well to industrial level fabrication requirements. Second, as feature sizes shrink into the nano-domain, it becomes increasingly difficult to accurately maintain those features over large depths and heights. The ability to produce these structures affordably and with high precision is critically important to a number of existing and emerging technologies such as metamaterials, nano-fluidics, nano-imprint lithography, and more. Summary To overcome these limitations, this study developed a novel and efficient method to etch complex 2D and 3D geometry in silicon with controllable sub-micron to nano-sized features with aspect ratios in excess of 500:1. This study utilized Metal-assisted Chemical Etching (MaCE) of silicon in conjunction with shape-controlled catalysts to fabricate structures such as 3D cycloids, spirals, sloping channels, and out-of-plane rotational structures. This study focused on taking MaCE from a method to fabricate small pores and silicon nanowires using metal catalyst nanoparticles and discontinuous thin films, to a powerful etching technology that utilizes shaped catalysts to fabricate complex, 3D geometry using a single lithography/etch cycle. The effect of catalyst geometry, etchant composition, and external pinning structures was examined to establish how etching path can be controlled through catalyst shape. The ability to control the rotation angle for out-of-plane rotational structures was established to show a linear dependence on catalyst arm length and an inverse relationship with arm width. A plastic deformation model of these structures established a minimum pressure gradient across the catalyst of 0.4 - 0.6 MPa. To establish the cause of catalyst motion in MaCE, the pressure gradient data was combined with force-displacement curves and results from specialized EBL patterns to show that DVLO encompassed forces are the most likely cause of catalyst motion. Lastly, MaCE fabricated templates were combined with electroless deposition of Pd to demonstrate the bottom-up filling of MaCE with sub-20 nm feature resolution. These structures were also used to establish the relationship between rotation angle of spiraling star-shaped catalysts and their center core diameter. Summary In summary, a new method to fabricate 3D nanostructures by top-down etching and bottom-up filling was established along with control over etching path, rotation angle, and etch depth. Out-of-plane rotational catalysts were designed and a new model for catalyst motion proposed. This research is expected to further the advancement of MaCE as platform for 3D nanofabrication with potential applications in thru-silicon-vias, photonics, nano-imprint lithography, and more.

Les transistors mono-électroniques (SETs) sont des dispositifs ayant un grand potentiel d'applications, comme la détection de charge ultra-sensible, la logique à basse consommation de puissance, la mémoire ou la métrologie. De plus, la possibilité de piéger un seul électron et de manipuler son état de spin pourrait permettre des applications en informatique quantique. Le silicium est un matériau intéressant pour fabriquer l'îlot d'un SET. Son gap semi-conducteur permet le fonctionnement du dispositif dans le régime à un seul électron ou trou et pourrait permettre d'étendre la plage d'opération du SET en température en augmentant l'énergie d'addition du diamant central de la valeur du gap. En outre, le silicium bénéficie de plus de quarante années d'expertise en microfabrication et d'une compatibilité avec la technologie métal-oxyde-semi-conducteur complémentaire (CMOS). Cependant, la fabrication de ces dispositifs fait face à de sérieuses limitations à cause de la taille nanométrique requise pour l'îlot. À ce jour, les procédés de fabrication proposés permettant l'opération à la température ambiante sont trop peu reproductibles pour permettre des applications à grande échelle. Dans ce mémoire de maîtrise, la fabrication de transistors mono-électroniques en silicium (Si-SETs) pour le traitement classique et quantique de l'information est réalisée avec un procédé nanodamascène. Le polissage chimico-mécanique (CMP) est introduit comme étape clef de la fabrication du transistor, permettant le contrôle au nanomètre près (nanodamascène) de l'épaisseur du transistor. Cet outil permet la fabrication de dispositifs ayant une géométrie auparavant impossible à réaliser et ouvre la porte à l'innovation technologique. De plus, un procédé de gravure du silicium par plasma à couplage inductif (ICP) est développé pour permettre la fabrication de nanostructures de silicium sur une nanotopographie alliant le nano et le 3D. Les Si-SETs fabriqués sont caractérisés à basse température et démontrent du blocage de Coulomb avec une énergie de charge de plus de 100 meV, soit quatre fois la température ambiante. De plus, le régime à un seul électron et les effets quantiques du confinement dans ce régime sont observés. Pour la première fois, le gap complet du silicium et les premiers diamants sont mesurés sur un dispositif fabriqué avec un procédé reproductible et industrialisable. Le diamant central voit son énergie d'addition augmentée de la valeur du gap du silicium, pour un total de plus de 1200 meV, soit 46 fois la température ambiante. Cette caractéristique pourrait ouvrir la porte à des applications en logique basse puissance dans un mode de transport à plusieurs électrons laissant circuler dix fois plus de courant dans l'état ouvert, tout en conservant le bas courant dans l'état fermé d'un SET.

Les solutions colloïdales constituées de nanoparticules en solution sont une famille d'objets aux propriétés optiques uniques. Leur utilisation comme élement de base à la fabrication de composants optiques sublongueur d'onde pourrait permettre la naissance de nouvelles applications en particulier dans le domaine de l'optique intégrée et de la détection biologique. La manipulation de ces particules reste toutefois un défi en raison de leur taille et de leur dispersion aléatoire dans un milieu liquide. Dans ce contexte, nous avons réalisé des nouveaux composants optiques grâce au développement de techniques de fabrication basées sur la méthode d'assemblage capillaire assisté par convection. Deux types de structures ont été réalisés puis évalués en terme de comportement optique : les dimères métalliques d'Au et les microsphères diélectriques de polystyrène assemblées en chaînes ou en réseaux. Pour les dimères, une étude fondamentale a été effectuée sur les phénomènes plasmoniques régissant les propriétés optiques de ces objets. Leur potentiel en tant que détecteur ultrasensible SERS et nanoantenne à boîtes quantiques a ensuite été approfondi. Pour les microsphères, une étude sur la propagation et la diffusion des modes de galerie présents dans ces objets a tout d'abord été réalisée dans le but d'en faire des candidats pour la détection ultrasensible. Les propriétés de guidage de la lumière dans des assemblages en chaîne ont ensuite été traitées. Afin de compléter ce travail un dernier composant optique a été développé en complément des guides et capteurs colloïdaux déjà réalisés. Il s'agit d'une nouvelle génération d'émetteurs localisés conçus pour un usage large et versatile et qu'il est possible de définir comme microsource de lumière blanche.

Diffractive zone-plate lenses are widely used as optics in high-resolution x-ray microscopes. The achievable resolution in such microscopes is presently not limited by the x-ray wavelength but by limitations in zone-plate nanofabrication. Thus, for the advance of high-resolution x-ray microscopy, progress in zone-plate nanofabrication methods are needed.   This Thesis describes the development of new nanofabrication processes for improved x-ray zone-plate optics. Cold development of the electron-beam resist ZEP7000 is applied to improve the resolution of soft x-ray Ni zone plates. The influence of developer temperature on resist contrast, resolution, and pattern quality is investigated. With an optimized process, Ni zone plates with outermost zone widths down to 13 nm are demonstrated. To enhance the diffraction efficiency of Ni zone plates, the concept of Ni-Ge zone plates is introduced. The applicability of Ni-Ge zone plates is first demonstrated in a proof-of-principle experiment, and then extended to cold-developed Ni zone plates with outermost zone widths down to 13 nm. For 15-nm Ni-Ge zone plates a diffraction efficiency of 4.3% at a wavelength of 2.88 nm is achieved, which is about twice the efficiency of state-of-the-art 15-nm Ni zone plates. To further increase both resolution and diffraction efficiency of soft x-ray zone plates, a novel fabrication process for W zone plates is developed. High resolution is provided by salty development of the inorganic electron-beam resist HSQ, and cryogenic RIE in a SF6 plasma is investigated for high-aspect-ratio W structuring. We demonstrate W zone plates with 12-nm outermost zone width and a W height of 90 nm, resulting in a 30% increase in theoretical diffraction efficiency compared to 13-nm efficiency-enhanced Ni-Ge zone plates. In addition to soft x-ray zone plates, some lenses for hard x-ray free-electron-laser applications were also fabricated during this Thesis work. Fabrication processes for the materials W, diamond, and Pt were developed. We demonstrate Pt and W-diamond zone plates with 100-nm outermost zone width and respective diffraction efficiencies of 8.2% and 14.5% at a photon energy of 8 keV. / QC 20111114

Blister-Based Laser-Induced Forward-Transfer (BB LIFT) is a new method of particle transfer, capable of projecting complex and fragile particles into the gas phase. The technique uses a laser pulse to deform a metal or polymer film on a transparent substrate. The deformation of the film creates a blister which can mechanically desorb particles adhered to the surface. This thesis covers the study of the underlying mechanisms of blister formation in relation to laser pulse duration and film properties, whilst also advancing upon the technique by developing new methods for particle transfer of 0-dimensional point particles, 1-dimensional nanotubes, and 2-dimensional crystals. Study of the blister formation was carried out on uncoated 200-400 nm Titanium films, using 120 fs and 7 ns laser pulses. The blisters were studied by Atomic Force Microscopy and optical analysis. Furthermore a theoretical model for the blister formation using ns laser pulses was developed using a linear heat transfer model, showing a good agreement between experiment and theory. From this model mechanisms for blister formation under both of these pulse durations were developed. It was concluded that ns laser pulses heat the thin film causing it to undergo thermal expansion where the temperature and thermal expansion properties of the film define the blister. Femtosecond pulses form blisters due to confined ablation of the film at the interface of the transparent substrate and the film. The expanding gas forces the metal to stretch, where the deformation is dictated by the Young’s modulus of the material with the major factor being the thickness of the titanium film. The velocity distribution of the desorbed material was studied by means of mass spectroscopy. An ionising laser pulse was focused a known distance from the donor film. The ejected particles crossed the laser beam, and with a controlled delay of the time between the blister pulse and ionisation pulse the velocities could be determined for fullerenes (C60) and gold coated silicon nanoparticles (Auroshells). Utilising C60 as the desorbed material we could identify that for ns BB-LIFT the C60 was emitted at a velocity mostly dependent upon the heat expansion coefficient for the titanium film, resulting in a velocity approximating 100 ms-1 with a secondary emission of fullerenes due to evaporation from the hot surface. However, for fs BB-LIFT this evaporated emission was not present and the velocities could be adjusted from 7-70 ms-1 by varying the Ti film thickness from 360 nm to 210 nm respectively. These results are consistent with the mechanisms proposed earlier. The spread of the desorbed particle beam was also studied for nanosecond and femtosecond laser-induced blisters utilising auroshells and C60. This was accomplished by placing a receiver platform at a known distance in front of the donor film in order to collect the desorbed particles. The radial spread was then analysed indicating a flat deposit approximately the size of the initial blister with a 5 degree spread from that point. This indicates that the desorbed beam is highly directional. From this it could be ascertained that the blisters do not form from a single point position on the film but expand uniformly with the area of laser irradiation defining the growth point of the blister. A problem with many molecular beam techniques is that large fragile molecules or nanoparticles cannot be introduced to the gas phase without causing damage to the particles. Studies into the desorption of Auroshells (150 nm diameter), C60 (1 nm), PCBM (a fragile exohedral fullerene), carbon nanotubes (1x1000 nm), and 2D films (1x10000x10000 nm) showed that these materials were successfully transferred from the donor film to a receiver plate without causing damage to the particles. This was determined via Raman, NMR, AFM, and SEM measurements. Lastly a technique that allowed the growth of carbon nanotubes directly on the donor film utilising a a multi-layered substrate was developed, enabling the removal and deposition of the nanotubes, without exposing them to any chemical treatment.

Orientadores: Gilberto Medeiros Ribeiro, Jose A. Brum / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin / Made available in DSpace on 2018-08-11T11:03:18Z (GMT). No. of bitstreams: 1 FernandezSiles_PabloRoberto_M.pdf: 9728988 bytes, checksum: 0fd358f0e4752f26b8ebfa6e4a5e3c5a (MD5) Previous issue date: 2006 / Resumo: A Oxidação anódica local em substratos tanto semicondutores quanto metálicos através do Microscópio de Força Atômica tem surgido ao longo dos últimos anos como uma das técnicas de litografia mais confiáveis e versáteis para a fabricação de dispositivos e estruturas em escala nanométrica. Embora aspectos fundamentais, como a dinâmica envolvida no processo de oxidação anódica em relação a diferentes parâmetros de controle, é ainda objeto de estudo. Pretende-se neste trabalho realizar uma caracterização de diferentes processos de litografia por AFM, com o objetivo de obter um melhor entendimento da cinética envolvida na oxidação assim como também determinar e quantificar a influência dos principais parâmetros de controle envolvidos no processo. Através de um processo de oxidação dinâmico, onde a ponta do microscópio encontra-se em movimento sobre a superfície da amostra durante o processo de oxidação, são determinadas as taxas de formação das estruturas de óxido em relação a parâmetros como a tensão aplicada na interface ponta-amostra, a umidade e a velocidade de varredura do microscópio. Finalmente, implementa-se a técnica para a fabricação de dispositivos em pequena escala. A construção de dispositivos passa por duas etapas de litografia, uma de ajuste grosso de padrões microscópicos, uma de ajuste fino onde linhas e demais geometrias são gravadas em uma escala de dezenas de nanômetros. O objetivo neste trabalho é de se fazer ambos os passos, sendo que a litografia fina será realizada por litografia por oxidação anódica local através do microscópio de força atômica. Para a definição das estruturas em escala nanométrica é proposta aqui, uma estrutura de duas camadas (PMMA-Ge), utilizada como resist. O sistema a ser estudado centra-se primeiramente nos pontos quânticos auto-formados (QDs). Pretende-se, em se integrando esta litografia e o crescimento de QDs, reunir o melhor de cada um destes processos, a precisão da litografia por oxidação anódica local e as propriedades eletrônicas limpas dos QDs, de maneira a estudar as propriedades eletrônicas de um pequeno número de QDs isolados / Abstract: Local Anodic Oxidation of conducting and non-conducting substrates by means of Atomic Force Microscopy has raised in the last years as a solid and versatile lithographic technique for fabrication of devices and structures in a nanometric scale. Although, fundamental aspects, as the kinetics involved during the oxidation, are still under study. The objective of this work is to develop a characterization process of this AFM lithographic technique aiming not only to obtain a better understanding of the kinetics involved in the oxidation process but also be able to determine and quantify the influence of the main processing parameters that control the anodic oxidation reaction in the probe-sample interface. By means of a dynamic oxidation process, where the AFM probe is scanning the sample's surface during the oxidation process, we determine the volumetric growth rates of the oxide patterns as a function of the applied voltage in the probe-sample interface, the humidity and the scanning rate of the microscope. As an example of the potential of this technique, it is implemented for the fabrication of devices in a sub-micrometric scale.The fabrication of nano-scaled devices is developed by means of two stages of lithography, first a course adjustment of microscopic patterns and then a fine adjustment where lines and other geometries are patterned in a scale of dezens of nanometers. The goal of this work is to develop both processes. Fine lithography will be done by means of local anodic oxidation (LAO oxidation) with an Atomic Force Microscopy (AFM). A two-layer (PMMA-Ge) resist structure is proposed here for de½nition of structures in a nanometric scale. The system to be studied is essentially based on the self-assembled quantum dots (QDs). The idea of the implementation of LAO oxidation and growth of QDs is to obtain the best performance of each of these processes, the high precision of local anodic lithography and the clean electronic properties of the QDs, aiming to study electronic properties of a small number of isolated QDs / Mestrado / Física da Matéria Condensada / Mestre em Física

Pour concevoir avec succès l'instrumentation nécessaire aux nouvelles technologies de fabrication avec une précision nanométrique, la méthodologie de conception doit prendre en compte de nombreux sujets différents liés à la chimie, à la physique, à la mécanique, à l'électronique et à l'automatisation, travaillant ensemble pour atteindre l'objectif souhaité. Dans cette thèse, cette méthodologie de conception a été mise en œuvre avec un grand nombre d’outils et d’approches permettant d’optimiser avec succès une méthode de nanofabrication appelée dépôt par couche atomique spatiale (SALD) afin de déposer des couches minces d’un matériau potentiellement utile en tant que composant du dispositifs à énergie solaire non-silicium, séparateurs d’eau photoélectrochimiques et composants électroniques transparents à couche mince, entre autres: oxyde cuivreux (Cu2O).En ce qui concerne la technologie de fabrication et la conception mécatronique, SALD est une technique de fabrication prometteuse qui permet la fabrication de films minces avec une précision nanométrique et avec la capacité de contrôler leurs propriétés mécaniques, électriques et cristallographiques. De plus, l'approche SALD utilisée dans cette thèse et dans le Laboratoire des matériaux et du génie physique (LMGP) fonctionne à l'air libre (sans chambre de dépôt) et constitue donc potentiellement une approche compatible avec l'industrie pour les films minces homogènes de grande surface fabrication avec un débit élevé. De plus, SALD peut être utilisé dans des conditions qui le rendent compatible avec les substrats flexibles et avec les approches de rouleau à rouleau (R2R). Enfin, SALD offre une flexibilité sur le processus de dépôt afin qu’il puisse être ajusté pour obtenir différentes propriétés sur les films fabriqués avec un minimum de modification de l’instrumentation.À l'aide de simulations CFD (Computational Fluid Dynamics), les phénomènes de la mécanique des fluides qui se produisent pendant le processus de dépôt dans le système SALD ont été analysés pour différentes configurations du réacteur. L'influence sur les propriétés du film a été étudiée et une validation avec des dépôts expérimentaux a été effectuée. Ensuite, en utilisant les connaissances et les directives obtenues avec les simulations CFD, et afin de réduire le coût et la complexité de la modification de certains composants mécaniques du système, un flux de travail comprenant la conception assistée par ordinateur (CAO) et la fabrication additive (également appelé impression 3D) impression) a été mis en place au LMGP pour la fabrication de l’un des composants principaux du système SALD à LMGP: la tête de dépôt. Ici, c'est la première fois qu'une telle technique de fabrication innovante est appliquée aux processus de nanofabrication en couches minces, offrant de nombreuses applications potentielles dans le domaine. Dans cette thèse, un tel flux de travail est présenté et expliqué, ainsi que les directives apprises et les limitations découvertes également présentées.Enfin, couches minces de Cu2O ont été déposé avec succès avec la méthode SALD. Le Cu2O est l’un des rares matériaux aux propriétés électroniques prometteuses en tant que semi-conducteur transparent de type p. Ici, les films de Cu2O fabriqués utilisant le système SALD à LMGP sont rapportés et leur conductivité de type p et leur cristallographie sont analysées.Les résultats de ces travaux fournissent des directives initiales pour la conception industrielle d’un système de fabrication à haut débit basé sur la technologie SALD, dans lequel la conception de ses composants est optimisée pour chaque matériau souhaité. Cette approche de conception rend également ce travail utile pour augmenter la quantité de matériaux compatibles avec le SALD, ainsi que pour développer davantage la méthodologie SALD dans des processus de fabrication innovants de matériaux et de dispositifs. / To successfully design the instrumentation needed for new manufacturing technologies with nanoscale precision, the design methodology must take into account many different topics related to chemistry, physics, mechanics, electronics and automation, working together to achieve the desired goal. In this thesis, this design methodology has been implemented with a large number of tools and approaches to successfully optimize a nanofabrication method called spatial atomic layer deposition (SALD) in order to deposit thin films. a potentially useful material as a component of non-silicon solar energy devices, photoelectrochemical water separators and transparent thin-film electronic components, among others: cuprous oxide (Cu2O).With respect to manufacturing technology and mechatronics design, SALD is a promising manufacturing technique that enables the fabrication of thin films with nanoscale precision and the ability to control their mechanical, electrical and crystallographic properties. In addition, the SALD approach used in this thesis and in the Laboratoire des Matèriaux et du Génie Physique(LMGP) works in the open air (without a repository) and is therefore potentially an industry-compatible approach to film Thin homogeneous high-area manufacturing with high throughput. In addition, SALD can be used under conditions that make it compatible with flexible substrates and roll-to-roll approaches (R2R). Finally, SALD offers flexibility on the deposit process so that it can be adjusted to obtain different properties on films manufactured with a minimum of instrumentation modification.Using CFD (Computational Fluid Dynamics) simulations, the fluid mechanics phenomena that occur during the deposition process in the SALD system were analyzed for different reactor configurations. The influence on the properties of the film was studied and a validation with experimental deposits was carried out. Then, using the knowledge and guidance obtained with CFD simulations, and to reduce the cost and complexity of modifying certain mechanical components of the system, a workflow that includes computer-aided design (CAD) and manufacturing additive (also called 3D printing) printing) was set up at the LMGP for the manufacture of one of the main components of the LMGP SALD system: the deposit head. Here, it is the first time that such an innovative manufacturing technique has been applied to thin-film nanofabrication processes, offering many potential applications in the field. In this thesis, such a workflow is presented and explained, along with learned guidelines and discovered limitations also presented.Finally, thin layers of Cu2O have been successfully deposited with the SALD method. Cu2O is one of the few materials with promising electronic properties as a p-type transparent semiconductor. Here, Cu2O films made using the LMGP SALD system are reported and their p-type conductivity and crystallography are analyzed.The results of this work provide initial guidance for the industrial design of a high throughput manufacturing system based on SALD technology optimized for each desired material. This design approach also makes this work useful for increasing the amount of SALD compatible materials, as well as for further developing the SALD methodology in innovative materials and device manufacturing processes.

No description available.