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Carbon Nanostructures As Thermal Interface Materials
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Book Synopsis Carbon Nanostructures as Thermal Interface Materials by : Muhammad Omar Memon
Download or read book Carbon Nanostructures as Thermal Interface Materials written by Muhammad Omar Memon and published by . This book was released on 2011 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: The power density of electronic packages has substantially increased. The thermal interface resistance involves more than 50% of the total thermal resistance in current high-power packages. The portion of the thermal budget spent on interface resistance is growing because die-level power dissipation densities are projected to exceed 100 W/cm2 in near future. There is an urgent need for advanced thermal interface materials (TIMs) that would achieve order-of-magnitude improvement in performance. Carbon nanotubes and nanofibers have received significant attention in the past because of its small diameter and high thermal conductivity. The present study is intended to overcome the shortcomings of commercially used thermal interface materials by introducing a compliant material which would conform to the mating surfaces and operate at higher temperatures. Thin film "labeled buckypaper" of CNF based Materials was processed and optimized. An experimental setup was designed to test processed materials in terms of thermal impedance as a function of load and materials density, thickness and thermal conductivity. Results show that the thermal impedance decreased in conjunction with the increasing heat-treatment temperature of CNFs. TIM using heat treated CNF showed a significant decrement of 54% in thermal impedance. Numerical simulations confirmed the validity of the experimental model. A parametric study was carried out which showed significant decrement in the thermal resistance with the decrease in TIM thickness. A transient spike power was carried out using two conditions; uniform heat pulse of 24 Watts, and power spikes of 24-96 Watts. The results show that heat treated CNF was 12% more temperature resistant than direct contact with more than 50% enhancement in heat transport across it.
Book Synopsis Carbon Nanotubes for Thermal Interface Materials in Microelectronic Packaging by : Wei Lin
Download or read book Carbon Nanotubes for Thermal Interface Materials in Microelectronic Packaging written by Wei Lin and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As the integration scale of transistors/devices in a chip/system keeps increasing, effective cooling has become more and more important in microelectronics. To address the thermal dissipation issue, one important solution is to develop thermal interface materials with higher performance. Carbon nanotubes, given their high intrinsic thermal and mechanical properties, and their high thermal and chemical stabilities, have received extensive attention from both academia and industry as a candidate for high-performance thermal interface materials.\r : The thesis is devoted to addressing some challenges related to the potential application of carbon nanotubes as thermal interface materials in microelectronics. These challenges include: 1) controlled synthesis of vertically aligned carbon nanotubes on various bulk substrates via chemical vapor deposition and the fundamental understanding involved; 2) development of a scalable annealing process to improve the intrinsic properties of synthesized carbon nanotubes; 3) development of a state-of-art assembling process to effectively implement high-quality vertically aligned carbon nanotubes into a flip-chip assembly; 4) a reliable thermal measurement of intrinsic thermal transport property of vertically aligned carbon nanotube films; 5) improvement of interfacial thermal transport between carbon nanotubes and other materials.\r : The major achievements are summarized.\r : 1. Based on the fundamental understanding of catalytic chemical vapor deposition processes and the growth mechanism of carbon nanotube, fast synthesis of high-quality vertically aligned carbon nanotubes on various bulk substrates (e.g., copper, quartz, silicon, aluminum oxide, etc.) has been successfully achieved. The synthesis of vertically aligned carbon nanotubes on the bulk copper substrate by the thermal chemical vapor deposition process has set a world record. In order to functionalize the synthesized carbon nanotubes while maintaining their good vertical alignment, an in situ functionalization process has for the first time been demonstrated. The in situ functionalization renders the vertically aligned carbon nanotubes a proper chemical reactivity for forming chemical bonding with other substrate materials such as gold and silicon.\r : 2. An ultrafast microwave annealing process has been developed to reduce the defect density in vertically aligned carbon nanotubes. Raman and thermogravimetric analyses have shown a distinct defect reduction in the CNTs annealed in microwave for 3 min. Fibers spun from the as-annealed CNTs, in comparison with those from the pristine CNTs, show increases of ~35% and ~65%, respectively, in tensile strength (~0.8 GPa) and modulus (~90 GPa) during tensile testing; an ~20% improvement in electrical conductivity (~80000 S m−1) was also reported. The mechanism of the microwave response of CNTs was discussed. Such an microwave annealing process has been extended to the preparation of reduced graphene oxide.\r : 3. Based on the fundamental understanding of interfacial thermal transport and surface chemistry of metals and carbon nanotubes, two major transfer/assembling processes have been developed: molecular bonding and metal bonding. Effective improvement of the interfacial thermal transport has been achieved by the interfacial bonding.\r : 4. The thermal diffusivity of vertically aligned carbon nanotube (VACNT, multi-walled) films was measured by a laser flash technique, and shown to be ~30 mm2 s−1 along the tube-alignment direction. The calculated thermal conductivities of the VACNT film and the individual CNTs are ~27 and ~540 W m−1 K−1, respectively. The technique was verified to be reliable although a proper sampling procedure is critical. A systematic parametric study of the effects of defects, buckling, tip-to-tip contacts, packing density, and tube-tube interaction on the thermal diffusivity was carried out. Defects and buckling decreased the thermal diffusivity dramatically. An increased packing density was beneficial in increasing the collective thermal conductivity of the VACNT film; however, the increased tube-tube interaction in dense VACNT films decreased the thermal conductivity of the individual CNTs. The tip-to-tip contact resistance was shown to be ~1×10−7 m2 K W−1. The study will shed light on the potential application of VACNTs as thermal interface materials in microelectronic packaging.\r : 5. A combined process of in situ functionalization and microwave curing has been developed to effective enhance the interface between carbon nanotubes and the epoxy matrix. Effective medium theory has been used to analyze the interfacial thermal resistance between carbon nanotubes and polymer matrix, and that between graphite nanoplatlets and polymer matrix.
Book Synopsis Nano-scale Heat Transfer in Nanostructures by : Jihong Al-Ghalith
Download or read book Nano-scale Heat Transfer in Nanostructures written by Jihong Al-Ghalith and published by Springer. This book was released on 2018-03-06 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book introduces modern atomistic techniques for predicting heat transfer in nanostructures, and discusses the applications of these techniques on three modern topics. The study of heat transport in screw-dislocated nanowires with low thermal conductivity in their bulk form represents the knowledge base needed for engineering thermal transport in advanced thermoelectric and electronic materials, and suggests a new route to lower thermal conductivity that could promote thermoelectricity. The study of high-temperature coating composite materials facilitates the understanding of the role played by composition and structural characterization, which is difficult to approach via experiments. And the understanding of the impact of deformations, such as bending and collapsing on thermal transport along carbon nanotubes, is important as carbon nanotubes, due to their exceptional thermal and mechanical properties, are excellent material candidates in a variety of applications, including thermal interface materials, thermal switches and composite materials.
Book Synopsis Synthesis of Thermal Interface Materials Made of Metal Decorated Carbon Nanotubes and Polymers by : Marion Odul Okoth
Download or read book Synthesis of Thermal Interface Materials Made of Metal Decorated Carbon Nanotubes and Polymers written by Marion Odul Okoth and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the synthesis of a low modulus, thermally conductive thermal interface materials (TIM) using metal decorated nanotubes as fillers. TIMs are very important in electronics because they act as a thermally-conductive medium for thermal transfer between the interface of a heat sink and an electronic package. The performance of an electronic package decreases with increasing operating temperature, hence, there exists a need to create a TIM which has high thermal conduction to reduce the operating temperature. The TIM in this study is made from metal decorated multi-walled carbon nanotubes (MWCNT) and Vinnapas®BP 600 polymer. The sample was functionalized using mild oxidative treatment with nitric acid (HNO3) or, with N-Methly-2-Pyrrolidone (NMP). The metals used for this experiment were copper (Cu), tin (Sn), and nickel (Ni). The metal nanoparticles were seeded using functionalized MWCNTs as templates. Once seeded, the nanotubes and polymer composites were made with or without sodium dodecylbenzene sulfonate (SDBS), as a surfactant. Thermal conductivity (k) measurement was carried out using ASTM D-5470 method at room temperature. This setup best models the working conditions of a TIM. The TIM samples made for this study showed promise in their ability to have significant increase in thermal conduction while retaining the polymer's mechanical properties. The highest k value that was obtained was 0.72 W/m-K for a well dispersed aligned 5 wt percent Ni@MWCNT sample. The Cu samples underperformed both Ni and Sn samples for the same synthesis conditions. This is because Cu nanoparticles were significantly larger than those of Ni and Sn. They were large enough to cause alloy scattering and too large to attach to the nanotubes. Addition of thermally-conductive fillers, such as exfoliated graphite, did not yield better k results as it sunk to the bottom during drying. The use of SDBS greatly increased the k values of the sample by reducing agglomeration. Increasing the amount of metal@MWCNT wt percent in the sample had negative or no effect to the k values. Shear testing on the sample shows it adheres well to the surface when pressure is applied, yet it can be removed with ease.
Book Synopsis High Performance Carbon Nanotubes for Thermal Interface Materials by : Win Hon Tan
Download or read book High Performance Carbon Nanotubes for Thermal Interface Materials written by Win Hon Tan and published by . This book was released on 2014 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modification of Carbon Nanotubes for Thermal Interface Material Application by : Rahayu Saniman Mohd Zin
Download or read book Modification of Carbon Nanotubes for Thermal Interface Material Application written by Rahayu Saniman Mohd Zin and published by . This book was released on 2009 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermal Characterization of One-Dimensional Carbon Nanostructures by : Eric Kenji Mayhew
Download or read book Thermal Characterization of One-Dimensional Carbon Nanostructures written by Eric Kenji Mayhew and published by . This book was released on 2013 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The excellent thermal properties of individual carbon nanostructures, such as carbon nanofibers (CNFs), carbon nanotubes (CNTs), and CNT fibers, have provided the impetus for the development of thermal interface materials that can incorporate these nanostructures. The thermal conductivity measurements of individual CNFs, CNT strands, CNT fibers, and CNT-polymer composite fibers are made using a Wollaston wire T-type probe method inside of a scanning electron microscope. CNFs are studied to determine the degree of improvement in structure and thermal conductivity that can be attained by annealing chemical vapor deposition grown CNFs. The results show a significant increase in thermal conductivity of CNFs that are annealed at 2800°C for 20 hours compared with the non-heat-treated samples. Thermal conductivity measurements are also made on CNT fibers, CNT-polymer composite fibers, and individual CNT strands pulled from the CNT fibers. The thermal conductivity values are, by far, the highest reported values for CNT fibers.
Book Synopsis Novel Carbon Nanotube Thermal Interfaces for Microelectronics by : Premkumar Nagarathnam
Download or read book Novel Carbon Nanotube Thermal Interfaces for Microelectronics written by Premkumar Nagarathnam and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermal interface layer can be a limiting element in the cooling of microelectronic devices. Conventional solders, pastes and pads are no longer sufficient to handle the high heat fluxes associated with connecting the device to the sink. Carbon nanotubes(CNTs) have been proposed as a possible thermal interface material(TI M), due to their thermal and mechanical properties, and prior research has established the effectiveness of vertically arranged CNT arrays to match the capabilities of the best conventional TIMs. However, to reach commercial applicability, many improvements need to be made in terms of improving thermal and mechanical properties as well as cost and manufacturing ease of the layer. Prior work demonstrated a simple method to transfer and bond CNT arrays through the use of a nanometer thin layer of gold as a bonding layer. This study sought to improve on that technique. By controlling the rate of deposition, the bonding temperature was reduced. By using different metals and thinner layers, the potential cost of the technique was reduced. Through the creation of a patterned array, a phase change element was able to be incorporated into the technique. The various interfaces created are characterized mechanically and thermally.
Book Synopsis Thermal Behaviour and Applications of Carbon-Based Nanomaterials by : Dimitrios V. Papavassiliou
Download or read book Thermal Behaviour and Applications of Carbon-Based Nanomaterials written by Dimitrios V. Papavassiliou and published by Elsevier. This book was released on 2020-04-01 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanocomposites with Carbon-based nanofillers (e.g., carbon nanotubes, graphene sheets and nanoribbons etc.) form a class of extremely promising materials for thermal applications. In addition to exceptional material properties, the thermal conductivity of the carbon-based nanofillers can be higher than any other known material, suggesting the possibility to engineer nanocomposites that are both lightweight and durable, and have unique thermal properties. This potential is hindered by thermal boundary resistance (TBR) to heat transfer at the interface between nanoinclusions and the matrix, and by the difficulty to control the dispersion pattern and the orientation of the nanoinclusions. Thermal Behaviour and Applications of Carbon-Based Nanomaterials: Theory, Methods and Applications explores heat transfer in nanocomposites, discusses techniques predicting and modeling the thermal behavior of carbon nanocomposites at different scales, and methods for engineering applications of nanofluidics and heat transfer. The chapters combine theoretical explanation, experimental methods and computational analysis to show how carbon-based nanomaterials are being used to optimise heat transfer. The applications-focused emphasis of this book makes it a valuable resource for materials scientists and engineers who want to learn more about nanoscale heat transfer. Offers an informed overview of how carbon nanomaterials are currently used for nanoscale heat transfer Discusses the major applications of carbon nanomaterials for heat transfer in a variety of industry sectors Details the major computational methods for the analysis of the thermal properties of carbon nanomaterials
Book Synopsis Thermal Diffusivity Measurements on Metals and Ceramics at High Temperatures by : R. L. Rudkin
Download or read book Thermal Diffusivity Measurements on Metals and Ceramics at High Temperatures written by R. L. Rudkin and published by . This book was released on 1961 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermal Transport in Carbon-Based Nanomaterials by : Gang Zhang
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
Book Synopsis Thermal Transport in Isolated Carbon Nanostructures and Associated Nanocomposites by : Nayandeep Kumar Mahanta
Download or read book Thermal Transport in Isolated Carbon Nanostructures and Associated Nanocomposites written by Nayandeep Kumar Mahanta and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanostructures, namely carbon nanotubes, nanofibers and graphene, owing to their extremely high thermal conductivities, hold promise for use as fillers in materials required for thermal management of electronics. Efficient thermal characterization holds the key to understanding the heat conduction mechanisms in the particular nanostructures and continued development of materials for novel applications. The present work involves development of dedicated techniques for characterization of the thermal conduction in individual carbon nanostructures and nanocomposites. The thermal flash technique developed for characterizing individual nanostructures provides a simple, accurate and reliable means for measuring thermal conductivity while managing to avoid the issues associated with conventional techniques. The thermal conductivities measured for vapor-grown carbon nanofibers and various graphene nanoplatelets were consistent with theoretical estimates based on the fundamentals of heat conduction in solids. Moreover, the results provide valuable evidence to support existing theories for explaining the differences between the various nanoscale manifestations of graphite. The investigation on isolated nanostructures was followed with the development and characterization of epoxy nanocomposites comprising graphite and graphene as fillers with the overarching goal of preparing composites with a thermal conductivity higher than 40 W/m-K. The thermal conductivities measured for some of the nanocomposites using the dual-mode heat flow meter, a steady-state heat technique developed in this work, were higher than the highest reported value in literature. The presence of large graphite flakes in conjunction with small amounts of graphene to reduce the overall thermal interface resistance were the principal reasons behind the extremely high thermal conductivity of 42.4 ± 4.8 W/m-K (nearly 250 times enhancement) for an epoxy composite with 30 wt% of graphite and 5 wt% of graphene.
Book Synopsis Electronic Properties of Carbon Nanotubes by : Jose Mauricio Marulanda
Download or read book Electronic Properties of Carbon Nanotubes written by Jose Mauricio Marulanda and published by IntechOpen. This book was released on 2011-07-27 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes (CNTs), discovered in 1991, have been a subject of intensive research for a wide range of applications. These one-dimensional (1D) graphene sheets rolled into a tubular form have been the target of many researchers around the world. This book concentrates on the semiconductor physics of carbon nanotubes, it brings unique insight into the phenomena encountered in the electronic structure when operating with carbon nanotubes. This book also presents to reader useful information on the fabrication and applications of these outstanding materials. The main objective of this book is to give in-depth understanding of the physics and electronic structure of carbon nanotubes. Readers of this book should have a strong background on physical electronics and semiconductor device physics. This book first discusses fabrication techniques followed by an analysis on the physical properties of carbon nanotubes, including density of states and electronic structures. Ultimately, the book pursues a significant amount of work in the industry applications of carbon nanotubes.
Book Synopsis Study of the Thermal Conductivity in Metal-coated Carbon Nanotubes Using Molecular Dynamics Atomistic Simulations by : Dinesh Kumar Bommidi
Download or read book Study of the Thermal Conductivity in Metal-coated Carbon Nanotubes Using Molecular Dynamics Atomistic Simulations written by Dinesh Kumar Bommidi and published by . This book was released on 2018 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: To improve the energy efficiency in many electronics and machinery applications, advanced Thermal Interface Materials (TIMs) with high heat dissipation ability and more pliability must be employed. Among a variety of promising choices to make the advanced TIMs, Vertically Aligned Carbon Nanotube (VACNT) turfs (arrays) outstand with their exceptional mechanical and thermal properties. Individual CNTs are quite flexible due to their quasi-one-dimensional structure and presence of strong sp2 bonds among the carbon atoms gives them great strength. Also, the dominance of ballistic phonon transport in the CNTs endows them superior thermal conductivity when compared to many metallic substrates. However, the defects in CNTs, misaligned axial contacts between CNTs in a CNT turf, and the CNTs/substrate resistance reduce the practical thermal conductivity of the material. It is hypothesized that the application of metal coatings on each CNT in a CNT turf would enhance the overall thermal conductivity of the material and improve the connectivity between the CNT turfs and the metallic substrate. As the diameter of the CNTs in a CNT turf is in the order of several nanometers, Molecular Dynamics (MD) atomistic simulations is selected as a tool which provide a deeper understanding in studying the thermal transport at the fundamental level. Thermal conduction in the metals is electron dominant whereas regular MD procedures are incapable of considering the energy exchange between these electrons and phonons. Therefore, a different mechanism called Two-temperature Model (TTM) coupled with Non-Equilibrium MD is used in this study and proved to be effective. MD code to procure the coefficient of thermal conductivity (kappa) was developed and the effects of the metal thickness, number of walls in the CNT and the role of diameter of CNT on kappa of the metal-coated CNTs was individually investigated. It was shown that the increase in the thickness of metal coating would impede the kappa of individual CNTs following an inverse power trend. Also, it was found that among the number of shells in the CNT and its diameter, the former parameter tends to contribute more towards the thermal transport than the latter. The results of this work are capable of predicting the optimal design structure for metal-coated VACNT composite for advanced thermal management applications.
Book Synopsis Nanotube Superfiber Materials by : Michael B. Jakubinek
Download or read book Nanotube Superfiber Materials written by Michael B. Jakubinek and published by Elsevier Inc. Chapters. This book was released on 2013-09-16 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Individual carbon nanotubes (CNTs) have been reported to have the highest thermal conductivities of any known material. However, significant variability exists both for the reported thermal conductivities of individual CNTs and the thermal conductivities measured for macroscopic CNT assemblies (e.g. CNT films, buckypapers, arrays, and fibers), which range from comparable to metals to aerogel-like. This chapter reviews the current status of the field, summarizing a wide selection of experimental results and drawing conclusions regarding present limitations of the thermal conductivity of CNT assemblies and opportunities for improvement of the performance of nanotube superfiber materials.
Book Synopsis Nano-Bio- Electronic, Photonic and MEMS Packaging by : C.P. Wong
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.
Book Synopsis Electronic Properties of Carbon Nanotubes by : Jose Mauricio Marulanda
Download or read book Electronic Properties of Carbon Nanotubes written by Jose Mauricio Marulanda and published by IntechOpen. This book was released on 2011-07-27 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon nanotubes (CNTs), discovered in 1991, have been a subject of intensive research for a wide range of applications. These one-dimensional (1D) graphene sheets rolled into a tubular form have been the target of many researchers around the world. This book concentrates on the semiconductor physics of carbon nanotubes, it brings unique insight into the phenomena encountered in the electronic structure when operating with carbon nanotubes. This book also presents to reader useful information on the fabrication and applications of these outstanding materials. The main objective of this book is to give in-depth understanding of the physics and electronic structure of carbon nanotubes. Readers of this book should have a strong background on physical electronics and semiconductor device physics. This book first discusses fabrication techniques followed by an analysis on the physical properties of carbon nanotubes, including density of states and electronic structures. Ultimately, the book pursues a significant amount of work in the industry applications of carbon nanotubes.
