Download or read book Thermal Conduction in Graphene and Graphene Multilayers written by Suchismita Ghosh and published by . This book was released on 2009 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been increasing interest in thermal conductivity of materials motivated by the heat removal issues in electronics and by the need of fundamental science to understand heat conduction at nanoscale [1, 2, 3]. This dissertation reports the results of the experimental investigation of heat conduction in graphene and graphene multilayers. Graphene is a planar single sheet of sp 2 -bonded carbon atoms arranged in honeycomb lattice. It reveals many unique properties, including the extraordinarily high carrier mobility. In order to measure the thermal conductivity of graphene we developed an original non-contact technique based on micro-Raman spectroscopy. The samples for this study were prepared by mechanical exfoliation and suspended across trenches in Si/SiO 2 substrates. The number of atomic planes was determined by deconvolution of the Raman 2D band. The suspended graphene flakes attached to the heat sinks were heated by the laser light focused in the middle. The Raman G peak's temperature sensitivity allowed us to monitor the local temperature change produced by the variation of the excitation laser power. A special calibration procedure was developed to determine the fraction of power absorbed by graphene. Our measurements revealed that single-layer graphene has an extremely high room-temperature thermal conductivity in the range 3800-5300 W/mK depending on the flake size and quality. It was also found that most of the heat near room temperature is transferred by acoustic phonons rather than electrons. Theoretical studies of the phonon thermal conduction in graphene, which included detail treatment of the Umklapp scattering, are in agreement with our experiments. The measurements were also extended to few-layer graphene. It was shown that the thermal conductivity reduces with the increasing number of layers approaching the bulk graphite limit. To validate the measurement technique we investigated the thermal conductivity of the polycrystalline graphene films and reduced graphene oxide films deposited on polyethylene terephthalate substrates. In this case we obtained much smaller values of thermal conductivity, which was explained by the strong acoustic phonon scattering on the grain boundaries. Obtained results are important for electronic applications of graphene and may lead to new methods of thermal management of nanoelectronic chips.
Download or read book Thermal Transport in Graphene Multilayers and Nanoribbons written by Samia Subrina and published by Proquest, UMI Dissertation Publishing. This book was released on 2012-07 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the electronic industry aggressively moves towards nanometer designs thermal issues are becoming increasingly important for the high-end electronic chips. One of the approaches to mitigate the self-heating problems is the high-heat-flux hot-spot removal via incorporation into the chip designs of materials with the high thermal conductivity. Graphene is found to be one of the best known heat conductors, thus it can be used in nanoelectronic and optoelectronic devices as a heat spreader component. Graphene, the latest isolated allotrope of carbon made of individual atomic sheets bound in two dimensions, shows many remarkable properties. A non-contact method of measuring G peak position of the Raman spectrum as a function of both the temperature of the graphene sample and the power of the heat source was used to measure the thermal conductivity of graphene. The samples in the experiment had approximately rectangle geometry and the assumption about the plane heat wave was used for the data extraction. In this dissertation research we propose to develop a model and numerical procedure for the (i) accurate modeling-based data extraction for the thermal conductivity measurements; and (ii) simulate heat propagation in semiconductor device structures with graphene layers incorporated as heat spreaders. To achieve the goals of this dissertation research we simulated the heat transport in graphene using the finite element method (FEM) with the help of COMSOL software package, which solves numerically the partial differential equations. The modeling based data extraction was necessary to determine thermal conductivity of the graphene flakes of arbitrary shape. It also substantially improved the accuracy of the measurements. The simulation of heat propagation in device structures with graphene heat spreaders allows one to assess the feasibility of the graphene high-heat-flux thermal management. We focused on understanding how thermal transport is influenced by a surface geometry of the sample and geometries of the heat sources. The simulation results showed that the size, shape and heat source geometry impact heat propagation in different ways and have to be included in the experimental data extraction. The simulation procedure provided a necessary input for next experiments on heat conduction in graphene structures e.g., graphene multi-layers and graphene-heat sink structures and other device-level thermal management applications. It was found that the incorporation of graphene or few-layer graphene (FLG) layers with proper heat sinks can substantially lower the temperature of the localized hot spots. The developed model and obtained results are important for the design of graphene heat spreaders and interconnects and lead to a new method of heat removal from nanoelectronic and 3-D chips.
Download or read book Unusual Enhancement in Intrinsic Thermal Conductivity of Multilayer Graphene by Tensile Strains written by and published by . This book was released on 2015 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: High basal plane thermal conductivity k of multi-layer graphene makes it promising for thermal management applications. Here we examine the effects of tensile strain on thermal transport in this system. Using a first principles Boltzmann-Peierls equation for phonon transport approach, we calculate the room-temperature in-plane lattice k of multi-layer graphene (up to four layers) and graphite under different isotropic tensile strains. The calculated in-plane k of graphite, finite mono-layer graphene and 3-layer graphene agree well with previous experiments. The dimensional transitions of the intrinsic k and the extent of the diffusive transport regime from mono-layer graphene to graphite are presented. We find a peak enhancement of intrinsic k for multi-layer graphene and graphite with increasing strain and the largest enhancement amplitude is about 40%. In contrast the calculated intrinsic k with tensile strain decreases for diamond and diverges for graphene, we show that the competition between the decreased mode heat capacities and the increased lifetimes of flexural phonons with increasing strain contribute to this k behavior. Similar k behavior is observed for 2-layer hexagonal boron nitride systems, suggesting that it is an inherent thermal transport property in multi-layer systems assembled of purely two dimensional atomic layers. This study provides insights into engineering k of multi-layer graphene and boron nitride by strain and into the nature of thermal transport in quasi-two-dimensional and highly anisotropic systems.
Download or read book Physics of Graphene written by Hideo Aoki and published by Springer Science & Business Media. This book was released on 2013-12-17 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a state of the art report of the knowledge accumulated in graphene research. The fascination with graphene has been growing very rapidly in recent years and the physics of graphene is now becoming one of the most interesting as well as the most fast-moving topics in condensed-matter physics. The Nobel prize in physics awarded in 2010 has given a tremendous impetus to this topic. The horizon of the physics of graphene is ever becoming wider, where physical concepts go hand in hand with advances in experimental techniques. Thus this book is expanding the interests to not only transport but optical and other properties for systems that include multilayer as well as monolayer graphene systems. The book comprises experimental and theoretical knowledge. The book is also accessible to graduate students.
Download or read book Graphene written by Wonbong Choi and published by CRC Press. This book was released on 2011-10-11 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the late 20th century, graphene—a one-atom-thick planar sheet of sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice—has garnered appreciable attention as a potential next-generation electronic material due to its exceptional properties. These properties include high current density, ballistic transport, chemical inertness, high thermal conductivity, optical transmittance, and super hydrophobicity at nanometer scale. In contrast to research on its excellent electronic and optoelectronic properties, research on the syntheses of a single sheet of graphene for industrial applications is in its nascent stages. Graphene: Synthesis and Applications reviews the advancement and future directions of graphene research in the areas of synthesis and properties, and explores applications, such as electronics, heat dissipation, field emission, sensors, composites, and energy.
Download or read book Thermal Conductivity 30 written by Daniela S. Gaal and published by DEStech Publications, Inc. This book was released on 2010 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook of Graphene Volume 8 written by Sulaiman Wadi Harun and published by John Wiley & Sons. This book was released on 2019-06-28 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: The eighth volume in a series of handbooks on graphene research and applications The Handbook of Graphene, Volume 8: Technology and Innovations discusses the role of graphene-based applications in technological advancements. Topics include graphene materials used in circuit board repairs; RFID antenna and sensor fabrication; and wearable healthcare electronics. Chapters present detailed information on: modeling methods used in graphene research; applications of graphene-on-silicon photonic integrated circuits; the development of graphene for engineering applications; and other graphene subjects of interest to scientists, chemists and physicists.
Download or read book Graphene written by Hongwei Zhu and published by Academic Press. This book was released on 2017-09-15 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene: Fabrication, Characterizations, Properties and Applications presents a comprehensive review of the current status of graphene, especially focused on synthesis, fundamental properties and future applications, aiming to giving a comprehensive reference for scientists, researchers and graduate students from various sectors. Graphene, a single atomic layer of carbon hexagons, has stimulated a lot of research interest owing to its unique structure and fascinating properties. The book is devoted to understanding graphene fundamentally yet comprehensively through a wide range of issues in the areas of materials science, chemistry, physics, electronics and biology. The book is an important resource of comprehensive knowledge pertinent to graphene and to related expanding areas. This valuable book will attract scientists, researchers and graduate students in physics and chemistry because it aims at providing all common knowledge of these communities including essential aspects of material synthesis and characterization, fundamental physical properties and detailed chapters focused on the most promising applications. Presents a comprehensive and up-to-date review of current research of graphene, especially focused on synthesis, fundamental properties and future applications Includes not only fundamental knowledge of graphene materials, but also an overview of special properties for different potential applications of graphene in the fields of solar cells, photodetectors, energy storage, composites, environmental materials and bio-materials Emphasizes graphene-based applications that are quickly emerging as potential building blocks for nanotechnological commercial applications
Download or read book Advanced Computational Nanomechanics written by Nuno Silvestre and published by John Wiley & Sons. This book was released on 2016-02-08 with total page 327 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains the latest research advances in computational nanomechanics in one comprehensive volume Covers computational tools used to simulate and analyse nanostructures Includes contributions from leading researchers Covers of new methodologies/tools applied to computational nanomechanics whilst also giving readers the new findings on carbon-based aggregates (graphene, carbon-nanotubes, nanocomposites) Evaluates the impact of nanoscale phenomena in materials
Download or read book Nano Bio Electronic Photonic and MEMS Packaging written by C.P. Wong and published by Springer Science & Business Media. This book was released on 2009-12-23 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanotechnologies are being applied to the biotechnology area, especially in the area of nano material synthesis. Until recently, there has been little research into how to implement nano/bio materials into the device level. “Nano and Bio Electronics Packaging” discusses how nanofabrication techniques can be used to customize packaging for nano devices with applications to biological and biomedical research and products. Covering such topics as nano bio sensing electronics, bio device packaging, NEMs for Bio Devices and much more.
Download or read book Materials for Sustainable Energy Storage at the Nanoscale written by Fabian Ifeanyichukwu Ezema and published by CRC Press. This book was released on 2023-07-21 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book Materials for Sustainable Energy Storage Devices at the Nanoscale anticipates covering all electrochemical energy storage devices such as supercapacitors, lithium-ion batteries (LIBs), and fuel cells, transformation and enhancement materials for solar cells, photocatalysis, etc. The focal objective of the book is to deliver stunning and current information to the materials application at nanoscale to researchers and scientists in our contemporary time towardthe enhancement of energy conversion and storage devices. However, the contents of the proposed book, Materials for Sustainable Energy Storage at the Nanoscale, will cover various fundamental principles and wide knowledge of different energy conversion and storage devices with respect to their advancement due to the emergence of nanoscale materials for sustainable storage devices. This book is targeted to be award-winning as well as a reference book for researchers and scientists working on different types of nanoscale materials-based energy storage and conversion devices. Features Comprehensive overview of energy storage devices, an important field of interest for researchers worldwide Explores the importance and growing impact of batteries and supercapacitors Emphasizes the fundamental theories, electrochemical mechanism, and its computational view point and discusses recent developments in electrode designing based on nanomaterials, separators, and fabrication of advanced devices and their performances
Download or read book Electronic Properties of Graphene Multilayers and Graphite Thin Films written by Julius De Rojas and published by . This book was released on 2011 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The purpose of this thesis is to study various electronic properties of graphene multilayers and graphite thin films. A Fortran program was developed to calculate the electronic band structure in the tight-binding approximation of graphene multilayers. The results were studied as a function of the number of graphene layers. The code accounts for band crossing, and allows tracking of each valence and conduction band. In addition, the density of states is calculated numerically using an analytic continuation technique. A subroutine determining the Fermi energy at a given density of electrons was written to calculate the Fermi energy and density of states at the Fermi level as a function of the number of layers. We then consider the band structure of graphite in the effective mass approximation. In the present work we calculate the density of states at the Fermi energy as the number of filled sub-bands increases. We show that the density of states oscillates as a function of graphite thickness. We use this to determine how the quantum size effect affects the critical temperature of a proximity system as the graphite film thickness is increased. We obtain an oscillatory function of the thickness and drive an analytic expression for the oscillation intervals. Recent experimental results are discussed in the light of the theory.
Download or read book Experimental and Theoretical Investigations of Thermal Transport in Graphene written by Mir Mohammad Sadeghi and published by . This book was released on 2015 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphene has been actively investigated because its unique structural, electronic, and thermal properties are desirable for a number of technological applications ranging from electronic to energy devices. The thermal transport properties of graphene can influence the device performances. Because of the high surface to volume ratio and confinement of phonons and electrons, the thermal transport properties of graphene can differ considerably from those in graphite. Developing a better understanding of thermal transport in graphene is necessary for rational design of graphene-based functional devices and materials. It is known that the thermal conductivity of single-layer graphene is considerably suppressed when it is in contact with an amorphous material compared to when it is suspended. However, the effects of substrate interaction in phonon transport in both single and multi-layer graphene still remains elusive. This work presents sensitive in-plane thermal transport measurements of few-layer and multi-layer graphene samples on amorphous silicon dioxide with the use of suspended micro-thermometer devices. It is shown that full recovery to the thermal conductivity of graphite has yet to occur even after the thickness of the supported multi-layer graphene sample is increased to 34 layers, which is considerably thicker than previously thought. This surprising finding is explained by the long intrinsic scattering mean free paths of phonons in graphite along both the basal-plane and cross-plane directions, as well as partially diffuse scattering of phonons by the graphene-amorphous support interface, which is treated by an interface scattering model developed for highly anisotropic materials. In addition, an experimental method is introduced to investigate electronic thermal transport in graphene and other layered materials through the measurement of longitudinal and transverse thermal and electrical conductivities and Seebeck coefficient under applied electric and magnetic fields. Moreover, this work includes an investigation of quantitative scanning thermal microscopy measurements of electrically biased graphene supported on a flexible polyimide substrate. Based on a triple scan technique and another zero heat flux measurement method, the temperature rise in flexible devices is found to be higher by more than one order of magnitude, and shows much more significant lateral heat spreading than graphene devices fabricated on silicon.
Download or read book Mechanics and Control of Solids and Structures written by Vladimir A. Polyanskiy and published by Springer Nature. This book was released on 2022-04-22 with total page 646 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a collection of papers prepared by the researches of the Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences (IPME RAS) on the occasion of the 30th anniversary of the establishment of the Institute. The IPME RAS is one of the leading research institutes of the Russian Academy of Sciences and consists of 18 research units (laboratories). The chapters cover the main research directions of the institute, including nano-,micro-, meso- and macro- mechanics and materials, with ,special emphasis on the problems of strength of materials and service life of structures.
Download or read book Handbook of Graphene written by Cengiz Ozkan and published by John Wiley & Sons. This book was released on 2019-06-12 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fifth volume in a series of handbooks on graphene research and applications Graphene is a valuable nanomaterial used in technology. The Handbook of Graphene: Graphene in Energy, Healthcare, and Environmental Applications is the fifth volume in the handbook series. The book's topics include: graphene nanomaterials in energy and environment applications and graphene used as nanolubricant. Within the handbook, three-dimensional graphene materials are discussed, as are synthesis and applications in electrocatalysts and electrochemical sensors. The battery topics cover: graphene and graphene-based hybrid composites for advanced rechargeable battery electrodes; graphene-based materials for advanced lithium-ion batteries; graphene-based materials for supercapacitors and conductive additives of lithium ion batteries. The book's graphene-based sensor information addresses flexible actuators, sensors, and supercapacitors.
Download or read book Electronic and Thermal Properties of Graphene written by Kyong Yop Rhee and published by Mdpi AG. This book was released on 2020-07 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue includes recent research articles and extensive reviews on graphene-based next-generation electronics, bringing together perspectives from different branches of science and engineering. The papers presented in this volume cover experimental, computational and theoretical aspects of the electrical and thermal properties of graphene and its applications in batteries, electrodes, sensors and ferromagnetism. In addition, this Special Issue covers many important state-of-the-art technologies and methodologies regarding the synthesis, fabrication, characterization and applications of graphene-based nanocomposites.
Download or read book Thermal Transport in Carbon Based Nanomaterials written by Gang Zhang and published by Elsevier. This book was released on 2017-06-13 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Transport in Carbon-Based Nanomaterials describes the thermal properties of various carbon nanomaterials and then examines their applications in thermal management and renewable energy. Carbon nanomaterials include: one-dimensional (1D) structures, like nanotubes; two-dimensional (2D) crystal lattice with only one-atom-thick planar sheets, like graphenes; composites based on carbon nanotube or graphene, and diamond nanowires and thin films. In the past two decades, rapid developments in the synthesis and processing of carbon-based nanomaterials have created a great desire among scientists to gain a greater understanding of thermal transport in these materials. Thermal properties in nanomaterials differ significantly from those in bulk materials because the characteristic length scales associated with the heat carriers, phonons, are comparable to the characteristic length. Carbon nanomaterials with high thermal conductivity can be applied in heat dissipation. This looks set to make a significant impact on human life and, with numerous commercial developments emerging, will become a major academic topic over the coming years. This authoritative and comprehensive book will be of great use to both the existing scientific community in this field, as well as for those who wish to enter it. Includes coverage of the most important and commonly adopted computational and experimental methods to analyze thermal properties in carbon nanomaterials Contains information about the growth of carbon nanomaterials, their thermal properties, and strategies to control thermal properties and applications, allowing readers to assess how to use each material most efficiently Offers a comprehensive overview of the theoretical background behind thermal transport in carbon nanomaterials
