Thermal Properties Of Graphene And Applications For Thermal Management Of High Power Density Electronics

In part two of this dissertation, I report the results of investigation of thermal conductivity of thin films made of a novel nanostructured graphene material, which consists of graphene nanoribbons encapsulated in single walled carbon nanotubes. The temperature dependent Raman spectrum of this material was measured in order to obtain the temperature coefficients of G + peak and 2D peaks. Using the Raman optothermal technique, I determine the local temperature rise due to laser heating from the shifts in Raman peak positions. A finite element analysis method was conducted to simulated heat dissipation in the samples and to determine their effective thermal conductivity. The obtained results suggest that this hybrid graphene-carbon nanotube material can be used as fillers in thermal interface materials.

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.

The need for advanced thermal management materials in electronic packaging has been widely recognized as thermal challenges become barriers to the electronic industry’s ability to provide continued improvements in device and system performance. With increased performance requirements for smaller, more capable, and more efficient electronic power devices, systems ranging from active electronically scanned radar arrays to web servers all require components that can dissipate heat efficiently. This requires that the materials have high capability of dissipating heat and maintaining compatibility with the die and electronic packaging. In response to critical needs, there have been revolutionary advances in thermal management materials and technologies for active and passive cooling that promise integrable and cost-effective thermal management solutions. This book meets the need for a comprehensive approach to advanced thermal management in electronic packaging, with coverage of the fundamentals of heat transfer, component design guidelines, materials selection and assessment, air, liquid, and thermoelectric cooling, characterization techniques and methodology, processing and manufacturing technology, balance between cost and performance, and application niches. The final chapter presents a roadmap and future perspective on developments in advanced thermal management materials for electronic packaging.

Efficient thermal management is becoming a critical issue for development of the next generation of electronics. As the size of electronic devices shrinks, the dissipated power density increases, demanding a better heat removal. The discovery of graphene's unique electrical and thermal properties stimulated interest of electronic industry to development of graphene based technologies. In this dissertation, I report the results of my investigation of thermal properties of graphene derivatives and their applications in thermal management. The dissertation consists of three parts. In the first part, I investigated thermal conductivity of graphene laminate films deposited on thermally insulating polyethylene terephthalate substrates. Graphene laminate is made of chemically derived graphene and few layer graphene flakes packed in overlapping structure. Two types of graphene laminate were studied: as deposited and compressed. The thermal conductivity of the laminate was found to be in the range from 40 W/mK to 90 W/mK at room temperature. It was established that the average size and the alignment of graphene flakes are parameters dominating the heat conduction. In the second part of this dissertation, I investigated thermal conductivity of chemically reduced freestanding graphene oxide films. It was found that the in-plane thermal conductivity of graphene oxide can be increased significantly using chemical reduction and temperature treatment. Finally, I studied the effect of defects on thermal conductivity of suspended graphene. The knowledge of the thermal conductivity dependence on the concentration of defects can shed light on the strength of the phonon - point defect scattering in two-dimensional materials. The defects were introduced to graphene in a controllable way using the low-energy electron beam irradiation. It was determined that as the defect density increases the thermal conductivity decreases down to about 400 W/mK, and then reveal saturation type behavior. The thermal conductivity dependence on the defect density was analyzed using the Boltzmann transport equation and molecular dynamics simulations. The obtained results are important for understanding phonon transport in two-dimensional systems and for practical applications of graphene in thermal management.

Learn about the most recent advances in 2D materials with this comprehensive and accessible text. Providing all the necessary materials science and physics background, leading experts discuss the fundamental properties of a wide range of 2D materials, and their potential applications in electronic, optoelectronic and photonic devices. Several important classes of materials are covered, from more established ones such as graphene, hexagonal boron nitride, and transition metal dichalcogenides, to new and emerging materials such as black phosphorus, silicene, and germanene. Readers will gain an in-depth understanding of the electronic structure and optical, thermal, mechanical, vibrational, spin and plasmonic properties of each material, as well as the different techniques that can be used for their synthesis. Presenting a unified perspective on 2D materials, this is an excellent resource for graduate students, researchers and practitioners working in nanotechnology, nanoelectronics, nanophotonics, condensed matter physics, and chemistry.

Continuous downscaling of Si complementary metal-oxide semiconductor (CMOS) technology and progress in high-power electronics demand more efficient heat removal techniques to handle the increasing power density and rising temperature of hot spots. For this reason, it is important to investigate thermal properties of materials at nanometer scale and identify materials with the extremely large or extremely low thermal conductivity for applications as heat spreaders or heat insulators in the next generation of integrated circuits. The thin films used in microelectronic and photonic devices need to have high thermal conductivity in order to transfer the dissipated power to heat sinks more effectively. On the other hand, thermoelectric devices call for materials or structures with low thermal conductivity because the performance of thermoelectric devices is determined by the figure of merit Z=S 2 [sigma]/ K, where S is the Seebeck coefficient, K and [sigma] are the thermal and electrical conductivity, respectively. Nanostructured superlattices can have drastically reduced thermal conductivity as compared to their bulk counterparts making them promising candidates for high-efficiency thermoelectric materials. Other applications calling for thin films with low thermal conductivity value are high-temperature coatings for engines. Thus, materials with both high thermal conductivity and low thermal conductivity are technologically important. The increasing temperature of the hot spots in state-of-the-art chips stimulates the search for innovative methods for heat removal. One promising approach is to incorporate materials, which have high thermal conductivity into the chip design. Two suitable candidates for such applications are diamond and graphene. Another approach is to integrate the high-efficiency thermoelectric elements for on-spot cooling. In addition, there is strong motivation for improved thermal interface materials (TIMs) for heat transfer from the heat-generating chip to heat-sinking units. This dissertation presents results of the experimental investigation and theoretical interpretation of thermal transport in the advanced engineered materials, which include thin films for thermal management of nanoscale devices, nanostructured superlattices as promising candidates for high-efficiency thermoelectric materials, and improved TIMs with graphene and metal particles as fillers providing enhanced thermal conductivity. The advanced engineered materials studied include chemical vapor deposition (CVD) grown ultrananocrystalline diamond (UNCD) and microcrystalline diamond (MCD) films on Si substrates, directly integrated nanocrystalline diamond (NCD) films on GaN, free-standing polycrystalline graphene (PCG) films, graphene oxide (GOx) films, and "pseudo-superlattices" of the mechanically exfoliated Bi 2 Te 3 topological insulator films, and thermal interface materials (TIMs) with graphene fillers.

Thermal Management for Opto-electronics Packaging and Applications A systematic guide to the theory, applications, and design of thermal management for LED packaging In Thermal Management for Opto-electronics Packaging and Applications, a team of distinguished engineers and researchers deliver an authoritative discussion of the fundamental theory and practical design required for LED product development. Readers will get a solid grounding in thermal management strategies and find up-to-date coverage of heat transfer fundamentals, thermal modeling, and thermal simulation and design. The authors explain cooling technologies and testing techniques that will help the reader evaluate device performance and accelerate the design and manufacturing cycle. In this all-inclusive guide to LED package thermal management, the book provides the latest advances in thermal engineering design and opto-electronic devices and systems. The book also includes: A thorough introduction to thermal conduction and solutions, including discussions of thermal resistance and high thermal conductivity materials Comprehensive explorations of thermal radiation and solutions, including angular- and spectra-regulation radiative cooling Practical discussions of thermally enhanced thermal interfacial materials (TIMs) Complete treatments of hybrid thermal management in downhole devices Perfect for engineers, researchers, and industry professionals in the fields of LED packaging and heat transfer, Thermal Management for Opto-electronics Packaging and Applications will also benefit advanced students focusing on the design of LED product design.

The continuing trend toward miniaturization and high power density electronics results in a growing interdependency between different fields of engineering. In particular, thermal management has become essential to the design and manufacturing of most electronic systems.Heat Transfer: Thermal Management of Electronics details how engineers can use

Thermal Management Materials for Electronic Packaging Practical resource exploring the theoretical and experimental basis as well as solutions for the development of new thermal management materials for electronic packaging Thermal Management Materials for Electronic Packaging: Preparation, Characterization, and Devices provides in-depth and systematic summaries on cutting-edge thermal management materials for high-power density electronic devices, introducing the preparation methods and application scenarios of thermal management materials for electronic packing, covering refinements of thermal conductivity theory and performance prediction models for multiphase composites, and overall focusing on key scientific issues related to the subject, such as the internal interface of new high thermal conductive substrate materials and the mechanism of spatial topology on performance. The text also discusses key issues on the design and preparation of thermal conductive substrate materials with high thermal conductive properties, including their characterization, properties, and manipulation, as well as the latest methods, techniques, and applications in this rapidly developing area. Sample topics covered in Thermal Management Materials for Electronic Packaging include: Basic concepts and laws of thermal conduction, heat conduction differential equation and finite solution, and thermal conductivity of solids Definition and classification of electronic packaging, thermal management in electronic equipment, and requirements of electronic packaging materials Synthesis and surface modification of high thermal conductive filler and the synthesis of substrates and preparation of thermal conductive composites with inorganic ceramic skeleton structure Assembly of thermal conductive materials in different dimensions and preparation of composite materials, and reliability analysis and environmental performance evaluation Thermal Management Materials for Electronic Packaging serves as an ideal reference for researchers and workers in related fields to significantly improve the mechanical and thermal management properties of materials, expand the material selection and design margin of substrates, and develop substrates that meet the application needs of different gradients.

This book focuses on the fundamental principles and recent progress in the field of electrical and thermal properties of polymer nanocomposites. The physical and chemical natures determining the electrical and thermal properties of polymer nanocomposites are discussed in detail. The authors describe the range of traditional and emerging polymer nanocomposites from nanoparticle and polymer composites to novel nanostructure based polymer nanocomposites. They include novel properties and potential applications, such as high-k, low-k, high thermal conductivity, antistatic, high voltage insulation, electric stress control, and thermal energy conversion among others.