46 research outputs found

    An Experimental and Computational Investigation into Laser-Based Synthesis and Spectrochemical Characterizations of Metal/intermetallic Nanoparticles with Engineered Interfacial Functionalities

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    Nanomaterials have, over the years, generated tremendous interests of scientists and engineers from nearly all disciplines. This interest has been due to a large number of desired physico-chemical properties such as magneto-optic properties, mechanical strength, melting points, charge transport behavior, and surface reactivity exhibiting unique size-dependent characteristics at the nanoscale. The unique interfacial properties are widely believed to be a result of high ratio of surface to bulk atoms as well as, bridging states in which nanoparticles exist between atomic and bulk materials. Thus, in the world of material processing and engineering, recent years have seen a surge in the use of wide classes of nanostructured materials as novel energetic, catalytic, semiconductor, and biomedical materials with engineered functionalities that find use in industrial, technological and defense applications. Therefore, it becomes imperative to develop fundamental understanding on the manufacturing and characterization routes that can allow the systematic tuning of the interfacial-property characteristics of advanced nanomaterials by tailoring their sizes and architectures. The current PhD thesis aims to address this grand-challenge engineering problem by investigating early-stage formations theoretically, synthesis and novel spectrochemical characterizations of advanced metal/intermetallic and composite nanoparticles (NPs) with engineered surface properties. Specifically, the thesis is categorized into two broad sections, namely laser-based synthesis studies and laser-based spectroscopic characterizations of NPs. The synthesis section presents theoretical investigations into the inception stage of NP formations, namely nucleation via numerical simulations. Briefly, this section aims to reveal the processing-structure-property relations of metal NPs synthesized via gas phase routes in an effort to relate the processing parameters to the size and morphology of the NPs, which in turn, dictates their interfacial energetic and catalytic behaviors. Then, using the obtained fundamental understandings a laser-based synthesis technique is presented for generating novel energetic metallic nanocomposites. The size, morphology and energetic activities of these materials are analyzed and tuned to improve the energetic properties. Finally, the laser spectroscopic characterization section focuses on experimental investigations by introducing laser induced breakdown spectroscopy (LIBS) as a relatively non-destructive and robust spectrochemical technique for the structural and chemical composition characterizations of composite NPs in a facile, yet effective manner

    Scanning near-field photon emission microscopy

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    Ph.DDOCTOR OF PHILOSOPH

    Recent Advances in Thin Film Electronic Devices

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    This reprint is a collection of the papers from the Special Issue “Recent Advances in Thin Film Electronic Devices” in Micromachines. In this reprrint, 1 editorial and 11 original papers about recent advances in the research and development of thin film electronic devices are included. Specifically, three research fields are covered: device fundamentals (5 papers), fabrication processes (5 papers), and testing methods (1 paper). The experimental data, simulation results, and theoretical analysis presented in this reprint should benefit those researchers in flat panel displays, flat panel sensors, energy devices, memories, and so on

    CMOS-Based Peptide Arrays

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    CMOS - Based Peptide Arrays Peptide arrays are an important tool in proteomics and peptidomics, allowing a large number of peptides to be synthesized on a common support and exposed to a solution of target molecules in parallel. In particle-based synthesis, the amino acids for in situ synthesis of peptides are transported to synthesis loci in solid particles and released upon melting, allowing an increase in density over liquid-based systems. This thesis focuses on the development of application-specific high voltage integrated circuits for electrostatic deposition of charged amino acid particles and their integration into a combinatorial peptide synthesis system. Transfer of amino acid particles from the aerosol to synthesis loci on the chip surface was investigated for a pixel pitch between 45 µm and 100 µm, and compatibility between the chips, particle transfer and the poly(ethylene glycol)methacrylate - based surface modifi¬cations was established. The first combinatorial syntheses on CMOS chips were performed with over 16,000 distinct synthesis sites per chip, at a density of 10,000 spots per cm2, which is a 25-fold increase over the 400 spots per cm2 currently available on laser-printed glass slides. For FLAG and HA peptide epitopes, immonostaining showed regular spots of comparable signal intensity over the whole chip area

    Microscopy and Analysis

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    Microscopes represent tools of the utmost importance for a wide range of disciplines. Without them, it would have been impossible to stand where we stand today in terms of understanding the structure and functions of organelles and cells, tissue composition and metabolism, or the causes behind various pathologies and their progression. Our knowledge on basic and advanced materials is also intimately intertwined to the realm of microscopy, and progress in key fields of micro- and nanotechnologies critically depends on high-resolution imaging systems. This volume includes a series of chapters that address highly significant scientific subjects from diverse areas of microscopy and analysis. Authoritative voices in their fields present in this volume their work or review recent trends, concepts, and applications, in a manner that is accessible to a broad readership audience from both within and outside their specialist area

    Laboratory directed research and development. FY 1995 progress report

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    Dynamic Laser Fault Injection Aided by Quiescent Photon Emissions in Embedded Microcontrollers: Apparatus, Methodology and Attacks

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    Internet of Things (IoT) is becoming more integrated in our daily life with the increasing number of embedded electronic devices interacting together. These electronic devices are often controlled by a Micro-Controller Unit (MCU). As an example, it is estimated that today’s well-equipped automobile uses more than 50 MCUs. Some MCUs contain cryptographic co-processors to enhance the security of the exchanged and stored data with a common belief that the data is secured and safe. However many MCUs have been shown to be vulnerable to Fault Injection (FI) attacks. These attacks can reveal shared secrets, firmware, and other confidential information. In addition, this extracted information obtained by attacks can lead to identification of new vulnerabilities which may scale to attacks on many devices. In general, FI on MCUs corrupt data or corrupt instructions. Although it is assumed that only authorized personnel with access to cryptographic secrets will gain access to confidential information in MCUs, attackers in specialized labs nowadays may have access to high-tech equipment which could be used to attack these MCUs. Laser Fault Injection (LFI) is gaining more of a reputation for its ability to inject local faults rather than global ones due to its precision, thus providing a greater risk of breaking security in many devices. Although publications have generally discussed the topic of security of MCUs, attack techniques are diverse and published LFI provides few and superficial details about the used experimental setup and methodology. Furthermore, limited research has examined the combination of both LFI and Photo-Emission Microscopy (PEM), direct modification of instructions using the LFI, control of embedded processor resets using LFI, and countermeasures which simultaneously thwart other aspects including decapsulation and reverse engineering (RE). This thesis contributes to the study of the MCUs’ security by analyzing their susceptibility to LFI attacks and PEM. The proposed research aims to build a LFI bench from scratch allowing maximum control of laser parameters. In addition, a methodology for analysis of the Device Under Attack (DUA) in preparation for LFI is proposed, including frontside/backside decapsulation methods, and visualization of the structure of the DUA. Analysis of attack viability of different targets on the DUA, including One-Time Programmable (OTP) memory, Flash memory and Static Random Access Memory (SRAM) was performed. A realistic attack of a cryptographic algorithm, such as Advanced Encryption Standard (AES) using LFI was conducted. On the other hand, countermeasures to the proposed attack techniques, including decapsulation/RE, LFI and PEM, were discussed. This dissertation provides a summary for the necessary background and experimental setup to study the possibility of LFI and PEM in different DUAs of two different technologies, specifically PIC16F687 and ARM Cortex-M0 LPC1114FN28102. Attacks performed on on-chip peripherals such as Universal Asynchronous Receiver/Transmitter (UART) and debug circuity reveal new vulnerabilities. This research is important for understanding attacks in order to design countermeasures for securing future hardware

    La nanoélectronique pour l'interfaçage neuronal : des nanofils de silicium à des dispositifs de carbone

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    In line with the technological progress of last decades a variety of adapted bioelectrical interfaces was developed to record electrical activity from the nervous system reaching from whole brain activity to single neuron signaling. Although neural interfaces have reached clinical utility and are commonly used in fundamental neuroscience, their performance is still limited. In this work we investigated alternative materials and techniques, which could improve the monitoring of neuronal activity of cultured networks, and the long-term performance of prospective neuroprosthetics. While silicon nanowire transistor arrays and diamond based microelectrodes are proposed for improving the spatial resolution and the electrode stability in biological environment respectively, the main focus of this thesis is set on the evaluation of graphene based field effect transistor arrays for bioelectronics. Due to its outstanding electrical, mechanical and chemical properties graphene appears as a promising candidate for the realization of chemically stable flexible electronics required for long-term neural interfacing. Here we demonstrate the outstanding neural affinity of pristine graphene and the realization of highly sensitive fast graphene transistors for neural interfaces.Dans la lignée des progrès technologiques récents en électronique, ces dernières décennies ont vu l’émergence d’une variété de systèmes permettant l’interface bioélectronique, allant de la mesure de l’activité électrique émise par l’ensemble du cerveau jusqu’à la mesure du signal émis par un neurone unique. Bien que des interfaces électroniques avec les neurones ont montré leur utilité pour des applications cliniques et sont communément utilisés par les neurosciences fondamentales, leurs performances sont encore très limitées, notamment en raison de l’incompatibilité relative entre les systèmes à l’état solide et le vivant. Dans ce travail de thèse, nous avons étudié des techniques et des matériaux nouveaux permettant une approche alternative et qui pourraient améliorer le suivi de l’activité de réseaux de neurones cultivés in situ et à terme la performance des neuroprothèses in vivo. Dans ce travail, des réseaux de nanofils de silicium et des microélectrodes en diamant sont élaborés pour respectivement améliorer la résolution spatiale et la stabilité des électrodes dans un environnement biologique. Un point important de cette thèse est également l’évaluation des performances de transistors à effet de champ en graphène pour la bio électronique. En raison des performances remarquables et combinées sur les aspects électrique, mécanique et chimique du graphène, ce matériau apparaît comme un candidat très prometteur pour la réalisation d’une électronique permettant une interface stable et sensible avec un réseau de neurones. Nous montrons dans ce travail l’affinité exceptionnelle des neurones avec une surface de graphène brut et la réalisation d’une électronique de détection rapide et sensible à base de transistor en graphène

    21st Century Nanostructured Materials

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    Nanostructured materials (NMs) are attracting interest as low-dimensional materials in the high-tech era of the 21st century. Recently, nanomaterials have experienced breakthroughs in synthesis and industrial and biomedical applications. This book presents recent achievements related to NMs such as graphene, carbon nanotubes, plasmonic materials, metal nanowires, metal oxides, nanoparticles, metamaterials, nanofibers, and nanocomposites, along with their physical and chemical aspects. Additionally, the book discusses the potential uses of these nanomaterials in photodetectors, transistors, quantum technology, chemical sensors, energy storage, silk fibroin, composites, drug delivery, tissue engineering, and sustainable agriculture and environmental applications
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