Download or read book Nanoscale Metal Thin Film Dewetting Via Nanosecond Laser Melting written by Yueying Wu and published by . This book was released on 2011 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoscale metal thin film dewetting via laser treatment is studied in this dissertation. The purpose is to understand: 1) the spatial and temporal nature of intrinsic instabilities; and 2) mass transportation involved in dewetting pattern evolution in metal thin films as well as in lithographically patterned nanostructures; and finally 3) to explore advanced control of metallic nanostructure fabrication via the confluence of top down nanolithography and pulsed laser induced dewetting. This study includes three sections. In first section, thin film Cu-Ni alloys ranging from 2-8nm were synthesized and laser irradiated. The evolution of the spinodal dewetting process is investigated as a function of the thin film composition which ultimately dictates the size distribution and spacing of the nanoparticles, and the optical measurements of the copper rich alloy nanoparticles revealed characteristic plasmonic peaks. In section two, the dewetting behavior of nanolithographically patterned copper rings on Silicon substrate was studied. The self assembly of the rings into ordered nanoparticle/nanodrop arrays was accomplished via nanosecond pulsed laser heating. The resultant length scale of the 13nm and 7nm thick copper rings was correlated to the competition between transport and instabilities time scales during the liquid lifetime of the melted copper rings. To explore the influence of different substrates with different surface energy, the pulsed laser heated assembly of lithographically patterned copper rings on SiO2 substrate was studied in the last section. The correlated transport and instabilities show modified timescales. It is demonstrated again that the original geometry dictates the instability pathway, which for narrow rings obeys the Rayleigh-Plateau instability and for wider rings are influenced by the thin film instability.
Download or read book Examining Wetting and Dewetting Processes in Thin films on Crystalline Substrates at the Nanoscale written by Sahar Hihath and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlling the wetting and dewetting of ultra-thin films on solid substrates is important for a variety of technological and fundamental research applications. These applications include film deposition for semiconductor manufacturing, the growth of nanowires through nanoparticle-based catalysis sites, to making ordered arrays of nanoscale particles for electronic and optical devices. However, despite the importance of these processes, the underlying mechanisms by which a film wets a surface or dewets from it is still often unclear and widely debated. In this dissertation we examine wetting and dewetting processes in three materials systems that are relevant for device applications with the ultimate goal of understanding what mechanisms drive the wetting (or dewetting) process in each case. First, we examine the formation of wetting layers between nanoparticle films and highly conductive GaAs substrates for spintronic applications. In this case, the formation of a wetting layer is important for nanoparticle adhesion on the substrate surface. Wetting layers can be made by annealing these systems, which causes elemental diffusion from nanoparticles into the substrate, thereby adhesion between the nanoparticles and the substrate. Here we investigate the feasibility of forming a wetting layer underneath nanoparticles post-annealing in a system of Fe3O4 nanoparticles on a (100) GaAs substrate by studying the interface structure and composition via Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDXS). Electron Energy-Loss fine structures of the Fe-L3,2 and O-K absorption edges were quantitatively analyzed to gain insight about the compositional gradient of the interface between the nanoparticles and the GaAs substrate. Additionally, real-space density functional theory calculations of the dynamical form factor was performed to confirm the experimental observations. Second, the fundamental mechanisms that govern the onset of dewetting of thin metal films in both liquid and solid state are investigated. Dewetting processes are used in numerous technological applications. For instance, the dewetting of thin films on substrates is used for making spatially ordered nanoparticle arrays for use in plasmonics, nanophotonics, and magnetics. [1] In addition to dewetting applications in industry and research, dewetting processes have adverse impact on the reliability of semiconductor devices as it can limit the functionality of metal contacts utilized in transistors at elevated temperatures. The morphological changes during dewetting have been studied previously in plan-view by Scanning Electron Microscopy (SEM) after the annealing is completed, and in some cases in cross-section via real-time Transmission Electron Microscopy (TEM). However, due to temporal limitations of image acquisition in TEM, which is in the range of milliseconds, it has not been possible thus far to investigate the dynamics of the dewetting process with high-speed time resolution from nano- to micro-seconds. To gain insights into the fundamental mechanisms involved in dewetting, the early stages of the dewetting process were investigated via Dynamic Transmission Electron Microscopy (DTEM) with nanosecond time and nanometer spatial resolution. The experiments were performed on plan-view TEM samples consisting of nickel thin-films on (100) silicon substrates with a 2-3 nm thick native oxide. The laser ablation dynamics were captured, which involved liquid phase dewetting of the nickel film followed by substrate fracture and nanoscale particle expulsion. Finally, to capture the full dynamics of the dewetting process the experiments were performed on a system of nickel thin-films on (100) Strontium Titanate (STO) substrates. Samples of nickel thin-films on STO substrates have lower thermal expansion coefficient mismatch compared to the system discussed above. Thus, the STO substrates did not fracture after laser irradiation and enabled us to capture the progress of hole growth with time. Valence Electron Energy Loss spectroscopy was used to find the thickness of the TEM sample in order to calculate the geometry and simulate the temperature fields via finite element analysis with COMSOL Multiphysics package. Spatio-temporal temperature plots acquired from finite element modeling suggests that both liquid and solid-state dewetting processes were observed depending upon the magnitude of the laser energy used.
Download or read book Nanoscale Pattern Formation from Laser Induced Thin Film Instabilities written by Sagar Prasad Yadavali and published by . This book was released on 2015 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed laser assisted pattern formation in single and bilayer metal films was investigated in this dissertation. The overall goals were: (1) to overcome limitations in conventional pulsed laser dewetting techniques, (2) to better understand the role of effects such as thermal gradients, dispersion forces, pressure gradients, and electric fields on pattern formation, and (3) to investigate nanostructure morphology and its progression in the dewetting of bilayer metal films. This study was divided into two parts. In the first part, pulsed laser-induced instabilities of single layer metal films was discussed. The spinodal dewetting of Au films, a novel Rayleigh-Taylor instability induced by pressure gradients, and the role of DC electric field on pattern formation is presented. In pulsed laser dewetting of Au, the trend in particle spacing and diameter was consistent with the predictions of classical spinodal dewetting theory. The early stage dewetting morphology changed from bicontinuous structures to hole like, and thermal gradient forces were found to be significantly weaker than dispersive forces in Au. Next, we showed through experiment and theory that nanoscale Rayleigh-Taylor instabilities can be seen in thin metal films. This instability was a result of pressure gradients developed when Au films were melted inside a bulk fluid like glycerol. One of the primary findings in this pattern formation was that the spacing of the nanoparticles was independent of the film thickness and could be tuned by the magnitude of the pressure gradients. Finally, we concluded this part by presenting the discovery of phase array self assembly of metallic nanoparticles under the application of a DC electric (E) field. In the second part, the morphology evolution under pulsed laser dewetting of a bilayer of the immiscible metals Ag and Co was investigated. We found multiple transitions in morphology for bilayers and correlated these transitions with an experimentally constructed dewetting morphology phase diagram. Finally, the role of thermal gradients was assessed in the formation of a variety of bimetal nanostructure. Work by our collaborator using computational non-linear dynamics showed that different nanoscale morphologies such as core-shell, embedded, or stacked cases could be formed in the Co-Ag system.
Download or read book Ultrafast Laser Nanostructuring written by Razvan Stoian and published by Springer Nature. This book was released on 2023-04-06 with total page 1243 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bringing together contributions from leading experts in the field, this book reviews laser processing concepts that allow the structuring of material beyond optical limits, and methods that facilitate direct observation of the underlying mechanisms by exploring direct structuring and self-organization phenomena. The capacity to nanostructure material using ultrafast lasers lays the groundwork for the next generation of flexible and precise material processing tools. Rapid access to scales of 100 nm and below in two and three dimensions becomes a factor of paramount importance to engineer materials and to design innovative functions. To reflect the dynamic nature of the field at all levels from basic science to applications, the book is divided into three parts, Fundamental Processes, Concepts of Extreme Nanostructuring, and Applications, each of which is comprehensively covered. This book will be a useful resource for graduate students and researchers in laser processing, materials engineering, and nanoscience.
Download or read book Dewetting of Thin Films on Flexible Substrates Via Direct write Laser Exposure written by Anthony Jesus Ferrer and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microelectromechanical systems (MEMS) have enabled a wide variety of technologies both in the consumer space and in industrial/research areas. At the market level, such devices advance by the invention and innovation of production techniques. Additionally, there has been increased demand for flexible versions of such MEMS devices. Thin film patterning, represents a key technology for the realization of such flexible electronics. Patterns and methods that can be directly written into the thin film allow for design modification on the fly with the need for harsh chemicals and long etching steps. Laser-induced dewetting has the potential to create patterns in thin films at both the microscopic and nanoscopic level without wasting deposited material. This thesis presents the first demonstration of high-speed direct-write patterning of metallic thin films that uses a laser-induced dewetting phenomenon to prevent material loss. The ability to build film material with this technique is explored using various scanning geometries. Finally, demonstrations of direct-write dewetting of a variety of thin films will be presented with special consideration for high melting point metals deposited upon polymer substrates.
Download or read book Dewetting Properties of Ag Ni Alloy Thin Films written by Benjamin Scott Wolf and published by . This book was released on 2017 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, pulsed laser induced dewetting of both patterned and continuous Nickel (Ni)-Silver(Ag) thin films was investigated extensively as a novel way to perform directed assembly of nano-particles. First, continuous Ni-Ag thin film dewetting was studied on both bulk and TEM (Transmission electron microscope) membrane substrates at a variety of compositions to better understand the dewetting dynamics of the Ni-Ag system. Then, patterned Ni-Ag thin film dewetting was studied on both bulk and TEM membrane substrates to understand how different patterns and thin film configurations effect nano-particle distribution and formation. All of this work was done in anticipation of the reception of a laser TEM attachment which will allow for in-situ pulsed laser induced dewetting experiments. Our results show that directed assembly of nano-particles is possible by using pulsed laser induced dewetting and that a variety of nano-particle formations and structures can be achieved through this method.
Download or read book High Speed Direct Imaging of Thin Metal Film Ablation by Movie mode Dynamic Transmission Electron Microscopy written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Obliteration of matter by pulsed laser beams is not only prevalent in science fiction movies, but finds numerous technological applications ranging from additive manufacturing over machining of micro- and nanostructured features to health care. Pulse lengths ranging from femtoseconds to nanoseconds are utilized at varying laser beam energies and pulse lengths, and enable the removal of nanometric volumes of material. While the mechanisms for removal of material by laser irradiation, i.e., laser ablation, are well understood on the micrometer length scale, it was previously impossible to directly observe obliteration processes on smaller scales due to experimental limitations for the combination of nanometer spatial and nanosecond temporal resolution. Here, we report the direct observation of metal thin film ablation from a solid substrate through dynamic transmission electron microscopy. Quantitative analysis reveals liquid-phase dewetting of the thin-film, followed by hydrodynamic sputtering of nano- to submicron sized metal droplets. We discovered unexpected fracturing of the substrate due to evolving thermal stresses. This study confirms that hydrodynamic sputtering remains a valid mechanism for droplet expulsion on the nanoscale, while irradiation induced stress fields represent limit laser processing of nanostructured materials. Ultimately, our results allow for improved safety during laser ablation in manufacturing and medical applications.
Download or read book Experimental Investigations of Nanosceond Pulsed Laser Micromachining of Metal Using Thin Film Microsensors written by Hong Seok Choi and published by . This book was released on 2007 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Miniaturized Transistors written by Lado Filipovic and published by MDPI. This book was released on 2019-06-24 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: What is the future of CMOS? Sustaining increased transistor densities along the path of Moore's Law has become increasingly challenging with limited power budgets, interconnect bandwidths, and fabrication capabilities. In the last decade alone, transistors have undergone significant design makeovers; from planar transistors of ten years ago, technological advancements have accelerated to today's FinFETs, which hardly resemble their bulky ancestors. FinFETs could potentially take us to the 5-nm node, but what comes after it? From gate-all-around devices to single electron transistors and two-dimensional semiconductors, a torrent of research is being carried out in order to design the next transistor generation, engineer the optimal materials, improve the fabrication technology, and properly model future devices. We invite insight from investigators and scientists in the field to showcase their work in this Special Issue with research papers, short communications, and review articles that focus on trends in micro- and nanotechnology from fundamental research to applications.
Download or read book Women in Science Chemistry written by Jennifer L. Schaefer and published by Frontiers Media SA. This book was released on 2022-02-08 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pulsed laser Induced Dewetting of Metallic Nanostructures written by Christopher Aidan Hartnett and published by . This book was released on 2016 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation explores the fluid dynamics of nano and microscale liquid metal filaments, with an emphasis on experimentally investigating the influences and causes of filament breakup and metallic nanostructure formation. Understanding and manipulating the liquid state properties of materials, especially metals, have the potential to advance the development of future technology, particularly nanoscale technology. The combination of top-down nanofabrication techniques with bottom-up, intrinsic self-assembly mechanisms are a powerful fusion, because it permits new and unusual nanostructures to be created, whilst revealing interesting nanoscale physics. In fluid dynamics, wetting and dewetting is the spontaneous natural process that occurs when a liquid supported on a substrate seeks to minimize its systems energy. Either by covering the substrate surface, in the case of wetting, or by rupturing and assembling into a collection of smaller liquid fragments; typically droplets, with minimal contact and surface area with the substrate and the surrounding gaseous environment. Due to metal's unique liquid state properties, like low viscosity and high surface energy, the dewetting phase is the prescient realm to experimentally access and study the governing dynamics, instabilities, and mass transport behind metallic nanostructure formation. The work contained in this dissertation seeks to address some basic scientific questions, such as: How to develop reasonably simple but predictive models to describe the competition between instability mechanisms that result in filament coalescence or fragmentation, as a function of filament extent? How to manipulate the intrinsic material properties of liquid metals, like surface energy, to initiate instabilities, like those similar to the Rayleigh-Plateau instability, to encourage self-assembly at the nanoscale? A focused and collaborative approach is contained herein where experiments will be used to drive theoretical and computational simulations and vice versa.
Download or read book Handbook of Laser Micro and Nano Engineering written by KOJI SUGIOKA. and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides a comprehensive review of the entire field of laser micro and nano processing, including not only a detailed introduction to individual laser processing techniques but also the fundamentals of laser-matter interaction and lasers, optics, equipment, diagnostics, as well as monitoring and measurement techniques for laser processing. Consisting of 11 sections, each composed of 4 to 6 chapters written by leading experts in the relevant field. Each main part of the handbook is supervised by its own part editor(s) so that high-quality content as well as completeness are assured. The book provides essential scientific and technical information to researchers and engineers already working in the field as well as students and young scientists planning to work in the area in the future. Lasers found application in materials processing practically since their invention in 1960, and are currently used widely in manufacturing. The main driving force behind this fact is that the lasers can provide unique solutions in material processing with high quality, high efficiency, high flexibility, high resolution, versatility and low environmental load. Macro-processing based on thermal process using infrared lasers such as CO2 lasers has been the mainstream in the early stages, while research and development of micro- and nano-processing are becoming increasingly more active as short wavelength and/or short pulse width lasers have been developed. In particular, recent advances in ultrafast lasers have opened up a new avenue to laser material processing due to the capabilities of ultrahigh precision micro- and nanofabrication of diverse materials. This handbook is the first book covering the basics, the state-of-the-art and important applications of the dynamic and rapidly expanding discipline of laser micro- and nanoengineering. This comprehensive source makes readers familiar with a broad spectrum of approaches to solve all relevant problems in science and technology. This handbook is the ultimate desk reference for all people working in the field.
Download or read book Nanoplasmonics written by Grégory Barbillon and published by BoD – Books on Demand. This book was released on 2017-06-21 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoplasmonics is a young topic of research, which is part of nanophotonics and nano-optics. Nanoplasmonics concerns to the investigation of electron oscillations in metallic nanostructures and nanoparticles. Surface plasmons have optical properties, which are very interesting. For instance, surface plasmons have the unique capacity to confine light at the nanoscale. Moreover, surface plasmons are very sensitive to the surrounding medium and the properties of the materials on which they propagate. In addition to the above, the surface plasmon resonances can be controlled by adjusting the size, shape, periodicity, and materials' nature. All these optical properties can enable a great number of applications, such as biosensors, optical modulators, photodetectors, and photovoltaic devices. This book is intended for a broad audience and provides an overview of some of the fundamental knowledges and applications of nanoplasmonics.
Download or read book Principles of Surface Enhanced Raman Spectroscopy written by Eric Le Ru and published by Elsevier. This book was released on 2008-11-17 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: SERS was discovered in the 1970s and has since grown enormously in breadth, depth, and understanding. One of the major characteristics of SERS is its interdisciplinary nature: it lies at the boundary between physics, chemistry, colloid science, plasmonics, nanotechnology, and biology. By their very nature, it is impossible to find a textbook that will summarize the principles needed for SERS of these rather dissimilar and disconnected topics. Although a basic understanding of these topics is necessary for research projects in SERS with all its many aspects and applications, they are seldom touched upon as a coherent unit during most undergraduate studies in physics or chemistry. This book intends to fill this existing gap in the literature. It provides an overview of the underlying principles of SERS, from the fundamental understanding of the effect to its potential applications. It is aimed primarily at newcomers to the field, graduate students, researchers or scientists, attracted by the many applications of SERS and plasmonics or its basic science. The emphasis is on concepts and background material for SERS, such as Raman spectroscopy, the physics of plasmons, or colloid science, all of them introduced within the context of SERS, and from where the more specialized literature can be followed. Represents one of very few books fully dedicated to the topic of surface-enhanced Raman spectroscopy (SERS) Gives a comprehensive summary of the underlying physical concepts around SERS Provides a detailed analysis of plasmons and plasmonics
Download or read book Biological Electrochemistry written by Glenn Dryhurst and published by Elsevier. This book was released on 2012-12-02 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biological Electrochemistry, Volume I is a result of a series of lectures given regarding the electrochemistry of small and large organic and inorganic molecules and how electrochemical information helps in understanding some of the biological redox reactions of these systems. This volume ultimately focuses on the electrochemistry of small and macromolecular organic compounds. This book is divided into seven chapters where each focuses on a particular organic compound. These compounds are quinones, catecholamines, phenothiazines, ascorbic acid, purines, vitamin B12 and related compounds, and proteins. Each chapter starts with a brief introduction to the compounds and then its structure and electrochemistry aspect. The last chapter gives a detailed discussion on different kinds of proteins and their electrochemistry aspects. This volume will be of help to students as well as electrochemists, biochemists, biologists, and other scientists in the field of biotechnology.
Download or read book Nanoscale Science and Technology written by Robert Kelsall and published by John Wiley & Sons. This book was released on 2005-11-01 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnology is a vital new area of research and development addressing the control, modification and fabrication of materials, structures and devices with nanometre precision and the synthesis of such structures into systems of micro- and macroscopic dimensions. Future applications of nanoscale science and technology include motors smaller than the diameter of a human hair and single-celled organisms programmed to fabricate materials with nanometer precision. Miniaturisation has revolutionised the semiconductor industry by making possible inexpensive integrated electronic circuits comprised of devices and wires with sub-micrometer dimensions. These integrated circuits are now ubiquitous, controlling everything from cars to toasters. The next level of miniaturisation, beyond sub-micrometer dimensions into nanoscale dimensions (invisible to the unaided human eye) is a booming area of research and development. This is a very hot area of research with large amounts of venture capital and government funding being invested worldwide, as such Nanoscale Science and Technology has a broad appeal based upon an interdisciplinary approach, covering aspects of physics, chemistry, biology, materials science and electronic engineering. Kelsall et al present a coherent approach to nanoscale sciences, which will be invaluable to graduate level students and researchers and practising engineers and product designers.
Download or read book Transmission Electron Microscopy written by C. Barry Carter and published by Springer. This book was released on 2016-08-24 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text is a companion volume to Transmission Electron Microscopy: A Textbook for Materials Science by Williams and Carter. The aim is to extend the discussion of certain topics that are either rapidly changing at this time or that would benefit from more detailed discussion than space allowed in the primary text. World-renowned researchers have contributed chapters in their area of expertise, and the editors have carefully prepared these chapters to provide a uniform tone and treatment for this exciting material. The book features an unparalleled collection of color figures showcasing the quality and variety of chemical data that can be obtained from today’s instruments, as well as key pitfalls to avoid. As with the previous TEM text, each chapter contains two sets of questions, one for self assessment and a second more suitable for homework assignments. Throughout the book, the style follows that of Williams & Carter even when the subject matter becomes challenging—the aim is always to make the topic understandable by first-year graduate students and others who are working in the field of Materials Science Topics covered include sources, in-situ experiments, electron diffraction, Digital Micrograph, waves and holography, focal-series reconstruction and direct methods, STEM and tomography, energy-filtered TEM (EFTEM) imaging, and spectrum imaging. The range and depth of material makes this companion volume essential reading for the budding microscopist and a key reference for practicing researchers using these and related techniques.
