Experimental Investigation Of Thermal Transport In Graphene And Hexagonal Boron Nitride

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Experimental Investigation of Thermal Transport in Graphene and Hexagonal Boron Nitride

Author : Insun Jo
Publisher :
ISBN 13 :
Total Pages : 270 pages
Book Rating : 4.:/5 (862 download)

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Book Synopsis Experimental Investigation of Thermal Transport in Graphene and Hexagonal Boron Nitride by : Insun Jo

Download or read book Experimental Investigation of Thermal Transport in Graphene and Hexagonal Boron Nitride written by Insun Jo and published by . This book was released on 2012 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-dimensional graphene, a single layer of graphite, has emerged as an excellent candidate for future electronic material due to its unique electronic structure and remarkably high carrier mobility. Even higher carrier mobility has been demonstrated in graphene devices using hexagonal boron nitride as an underlying dielectric support instead of silicon oxide. Interestingly, both graphene and boron nitride exhibit superior thermal properties, therefore may potentially offer a solution to the increasingly severe heat dissipation problem in nanoelectronics caused by increased power density. In this thesis, we focus on the investigation of the thermal properties of graphene and hexagonal boron nitride. First, scanning thermal microscopy based on a sub-micrometer thermocouple at the apex of a microfabricated tip was employed to image the temperature profiles in electrically biased graphene devices with ~ 100 nm scale spatial resolution. Non-uniform temperature distribution in the devices was observed, and the "hot spot" locations were correlated with the charge concentrations in the channel, which could be controlled by both gate and drain-source biases. Hybrid contact and lift mode scanning has enabled us to obtain the quantitative temperature profiles, which were compared with the profiles obtained from Raman-based thermometry. The temperature rise in the channel provided an important insight into the heat dissipation mechanism in Joule-heated graphene devices. Next, thermal conductivity of suspended single and few-layer graphene was measured using a micro-bridge device with built-in resistance thermometers. Polymer-assisted transfer technique was developed to suspend graphene layers on the pre-fabricated device. The room temperature thermal conductivity values of 1-7 layer graphene were measured to be lower than that of bulk graphite, and the value appeared to increase with increasing sample thickness. These observations can be explained by the impact of the phonon scattering by polymer residue remaining on the sample surfaces. Lastly, thermal conductivity of few-layer hexagonal boron nitride sample was measured by using the same device and technique used for suspended graphene. Measurements on samples with different suspended lengths but similar thickness allowed us to extract the intrinsic thermal conductivity of the samples as well as the contribution of contact thermal resistance to the overall thermal measurement. The room temperature thermal conductivity of 11 layer sample approaches the basal-plane value reported in the bulk sample. Lower thermal conductivity was measured in a 5 layer sample than an 11 layer sample, which again supports the polymer effect on the thermal transport in few-layer hexagonal boron nitride.

Experimental Investigations of Thermal Transport in Carbon Nanotubes, Graphene and Nanoscale Point Contacts

Author : Michael Thompson Pettes
Publisher :
ISBN 13 :
Total Pages : 278 pages
Book Rating : 4.:/5 (732 download)

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Book Synopsis Experimental Investigations of Thermal Transport in Carbon Nanotubes, Graphene and Nanoscale Point Contacts by : Michael Thompson Pettes

Download or read book Experimental Investigations of Thermal Transport in Carbon Nanotubes, Graphene and Nanoscale Point Contacts written by Michael Thompson Pettes and published by . This book was released on 2011 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: As silicon-based transistor technology continues to scale ever downward, anticipation of the fundamental limitations of ultimately-scaled devices has driven research into alternative device technologies as well as new materials for interconnects and packaging. Additionally, as power dissipation becomes an increasingly important challenge in highly miniaturized devices, both the implementation and verification of high mobility, high thermal conductivity materials, such as low dimensional carbon nanomaterials, and the experimental investigation of heat transfer in the nanoscale regime are requisite to continued progress. This work furthers the current understanding of structure-property relationships in low dimensional carbon nanomaterials, specifically carbon nanotubes (CNTs) and graphene, through use of combined thermal conductance and transmission electron microscopy (TEM) measurements on the same individual nanomaterials suspended between two micro-resistance thermometers. Through the development of a method to measure thermal contact resistance, the intrinsic thermal conductivity, [kappa], of multi-walled (MW) CNTs is found to correlate with TEM observed defect density, linking phonon-defect scattering to the low [kappa] in these chemical vapor deposition (CVD) synthesized nanomaterials. For single- (S) and double- (D) walled (W) CNTs, the [kappa] is found to be limited by thermal contact resistance for the as-grown samples but still four times higher than that for bulk Si. Additionally, through the use of a combined thermal transport-TEM study, the [kappa] of bi-layer graphene is correlated with both crystal structure and surface conditions. Theoretical modeling of the [kappa] temperature dependence allows for the determination that phonon scattering mechanisms in suspended bi-layer graphene with a thin polymeric coating are similar to those for the case of graphene supported on SiO2. Furthermore, a method is developed to investigate heat transfer through a nanoscale point contact formed between a sharp silicon tip and a silicon substrate in an ultra high vacuum (UHV) atomic force microscope (AFM). A contact mechanics model of the interface, combined with a heat transport model considering solid-solid conduction and near-field thermal radiation leads to the conclusion that the thermal resistance of the nanoscale point contact is dominated by solid-solid conduction.

Thermal Transport in Low-dimensional Materials

Author : Prabhakar Marepalli
Publisher :
ISBN 13 :
Total Pages : 360 pages
Book Rating : 4.:/5 (94 download)

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Book Synopsis Thermal Transport in Low-dimensional Materials by : Prabhakar Marepalli

Download or read book Thermal Transport in Low-dimensional Materials written by Prabhakar Marepalli and published by . This book was released on 2015 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent years have witnessed a paradigm shift in the world of electronics. Researchers have not only continued to postpone the long dreaded end-of-Moore’s-law, but have also opened up a new world of possibilities with electronics. The future of electronics is widely anticipated to be dominated by wearable and implantable devices, the realization of which will be made possible by the discovery of new materials. Graphene and hexagonal boron nitride (hBN) are two such materials that have shown promising properties to make these devices possible. It has been shown that an energy bandgap can be opened in graphene by patterning it as a narrow ribbon, by applying an electric displacement field to a bilayer configuration, and by other means. The possibility of tuning the bandgap makes graphene an ideal channel material for future electronics. Similarly, hexagonal boron nitride (hBN) and its ribbon configurations have been shown to be excellent dielectric materials. In addition, the similarities in the atomic configurations of graphene and hBN allow them to conform extremely well to each other, achieving atomically smooth interfaces. Graphene devices on hBN substrates have been shown to have mobilities an order of magnitude larger than graphene devices fabricated on silicon dioxide. In addition to their outstanding electrical properties, graphene and hBN have been shown to have excellent thermal properties compared to their traditional counterparts (silicon and silicon dioxide, respectively). More specifically, these materials have been shown to have size dependent thermal properties which may be used to tune device performance. In this thesis, we study the thermal transport of three important classes of materials – graphene nanoribbons, hBN nanoribbons and graphene-hBN heterostructures using the phonon Boltzmann transport equation in a linearized framework. An exact solution of the Boltzmann transport equation is obtained ensuring that normal and umklapp phonon scattering processes are appropriately treated. In the first part of the thesis, we present a computational technique called method of automatic code differentiation to calculate sensitivities in nanoscale thermal transport simulations. Key phonon parameters like force constants, group velocities, the Gruneisen parameter, etc., which can be expressed as sensitivities or derivatives, are computed using this technique. The derivatives computed using this technique are exact and can be generalized to any order with minimal effort. This technique can be unintrusively integrated with existing first-principles simulation codes to obtain the sensitivities of parameters computed therein to chosen inputs. The next focus is to investigate the thermal properties of three main classes of materials – graphene nanoribbons, hBN nanoribbons,and graphene-hBN heterostructures. For nanoribbons, we consider ribbons of varying widths to investigate the transition of key thermal properties with width. The lattice structure of the ribbon structures considered is fully resolved. An efficient parallelization technique is developed to handle the large number of atoms in a unit cell. The thermal conductivity is obtained by an iterative solution of the linearized Boltzmann transport equation. For graphene and hBN ribbons, we find that the thermal conductivity increases with the ribbon width following a power-law trend. The rate of increase of thermal conductivity with width for hBN ribbons is found to be slower compared to graphene. Flexural phonons are found to contribute to the majority of heat conduction in both the materials. Frequency- and polarization-resolved transport is analyzed for ribbon of all widths. The thermal conductivity of single- and few-layer hexagonal boron nitride is also computed and compared with measured data. It is found that the thermal conductivity of hBN based nanostructures (single-layer, few-layer and ribbons) is around 6-8 times smaller than that for the corresponding graphene-based nanostructure. The effect of strain in both these materials is investigated. We find that the thermal conductivity of single-layer hBN is very sensitive to strain whereas graphene shows relatively less sensitivity for the same strains. Finally, thermal transport in graphene-hBN heterostructures is simulated. Two different structures are considered – single-layer graphene on an hBN substrate, and bilayer graphene on an hBN substrate. Substrates of different thickness are considered. Due to the weak interlayer coupling in these heterostructures, it is found that the phonon dispersion remains largely unchanged from the dispersions of the individual layers. The only difference in dispersion is noticed for flexural phonons, which are the only modes affected by interlayer coupling. The addition of an hBN layer underneath the graphene/bilayer graphene layer is found to drastically reduce the thermal conductivity of the heterostructures. This reduction is due to breakdown of the selection rule for flexural phonons which results in increased scattering channels for these phonons. The thermal conductivity gradually decreases, saturating to a bulk value with an increase in the number of hBN layers. The results presented in this thesis are expected to help guide the design of graphene/hBN based flexible electronics.

Experimental and Theoretical Investigations of Thermal Transport in Graphene

Author : Mir Mohammad Sadeghi
Publisher :
ISBN 13 :
Total Pages : 246 pages
Book Rating : 4.:/5 (987 download)

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Book Synopsis Experimental and Theoretical Investigations of Thermal Transport in Graphene by : Mir Mohammad Sadeghi

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.

Thermoelectricity and Heat Transport in Graphene and Other 2D Nanomaterials

Author : Serhii Shafraniuk
Publisher : Elsevier
ISBN 13 : 0323444903
Total Pages : 534 pages
Book Rating : 4.3/5 (234 download)

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Book Synopsis Thermoelectricity and Heat Transport in Graphene and Other 2D Nanomaterials by : Serhii Shafraniuk

Download or read book Thermoelectricity and Heat Transport in Graphene and Other 2D Nanomaterials written by Serhii Shafraniuk and published by Elsevier. This book was released on 2017-07-15 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermoelectricity and Heat Transport in Graphene and Other 2D Nanomaterials describes thermoelectric phenomena and thermal transport in graphene and other 2-dimentional nanomaterials and devices. Graphene, which is an example of an atomic monolayered material, has become the most important growth area in materials science research, stimulating an interest in other atomic monolayeric materials. The book analyses flow management, measurement of the local temperature at the nanoscale level and thermoelectric transducers, with reference to both graphene and other 2D nanomaterials. The book covers in detail the mechanisms of thermoelectricity, thermal transport, interface phenomena, quantum dots, non-equilibrium states, scattering and dissipation, as well as coherent transport in low-dimensional junctions in graphene and its allotropes, transition metal dichalcogenides and boron nitride. This book aims to show readers how to improve thermoelectric transducer efficiency in graphene and other nanomaterials. The book describes basic ingredients of such activity, allowing readers to gain a greater understanding of fundamental issues related to the heat transport and the thermoelectric phenomena of nanomaterials. It contains a thorough analysis and comparison between theory and experiments, complemented with a variety of practical examples. Shows readers how to improve the efficiency of heat transfer in graphene and other nanomaterials with analysis of different methodologies Includes fundamental information on the thermoelectric properties of graphene and other atomic monolayers, providing a valuable reference source for materials scientists and engineers Covers the important models of thermoelectric phenomena and thermal transport in the 2D nanomaterials and nanodevices, allowing readers to gain a greater understanding of the factors behind the efficiency of heat transport in a variety of nanomaterials

Nanotechnology for Defence Applications

Author : Narendra Kumar
Publisher : Springer Nature
ISBN 13 : 3030298809
Total Pages : 341 pages
Book Rating : 4.0/5 (32 download)

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Book Synopsis Nanotechnology for Defence Applications by : Narendra Kumar

Download or read book Nanotechnology for Defence Applications written by Narendra Kumar and published by Springer Nature. This book was released on 2019-11-01 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the application of nanoscience and nanotechnology in military defence strategies. Both historical and current perspectives on military technologies are discussed. The book provides comprehensive details on current trends in the application of nanotechnology to ground, air, and naval specializations. Furthermore, nanotechnology-enabled high energy explosives and propellants, chemical, biological, radiation, and nuclear threats and their detection/protection, and camouflage and stealth for signature management of military targets in multispectral wavelength signals are analyzed. The book also covers nanotechnology-enabled armor and platforms, which may serve as lightweight and high mechanical strength options in contrast to conventional systems. Finally, the book also emphasizes future military applications of nanotechnology and its integration into ‘smart’ materials. Provides comprehensive details on trends in the application of nanotechnology to ground, air, and naval defence systems; Examines the application of nanoscience and nanotechnology in military defence strategies; Offers pathways and research avenues for development of nanotechnology and materials applications in military capacities.

Unusual Enhancement in Intrinsic Thermal Conductivity of Multilayer Graphene by Tensile Strains

Author :
Publisher :
ISBN 13 :
Total Pages : 7 pages
Book Rating : 4.:/5 (946 download)

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Book Synopsis Unusual Enhancement in Intrinsic Thermal Conductivity of Multilayer Graphene by Tensile Strains by :

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.

The Thermal Effect of Hexagonal Boron Nitride Supports in Graphene Devices

Author : David Seiji Kar Liang Choi
Publisher :
ISBN 13 :
Total Pages : 238 pages
Book Rating : 4.:/5 (19 download)

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Book Synopsis The Thermal Effect of Hexagonal Boron Nitride Supports in Graphene Devices by : David Seiji Kar Liang Choi

Download or read book The Thermal Effect of Hexagonal Boron Nitride Supports in Graphene Devices written by David Seiji Kar Liang Choi and published by . This book was released on 2018 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental understanding of thermal dissipation and energy transport is necessary for designing robust electronic systems and energy conversion devices. In many of these systems, minimizing the operating temperature of the working components is required for increasing the performance, lifetime, efficiency, and reliability of the device. For example, hot spots in transistors caused by the conversion of electronic energy to thermal energy has become a bottleneck in the continued scaling of microelectronics. As the demand for compact, highly conformable and mobile electronics continues to push the limit of miniaturization, these phenomena increasingly occur at the nanoscale. At these length scales, the governing physical principles differ from classical laws based on continuum mechanics and instead require a quantum mechanical treatment. The thermal transport properties of traditional three-dimensional (3D) heat conducting materials such as the metal interconnects in nanoelectronic devices tend to degrade as the critical dimension is reduced. In contrast, the thermal properties of a new class of van der Waals-based two-dimensional (2D) materials can show different size confinement effects that can potentially be utilized for thermal management. First realized by the isolation of graphene, these materials have become attractive candidates for future-generation electronic and thermal components. Due to their atomic thinness, the properties of 2-D materials are highly sensitive to their operating environment. The studies in this dissertation therefore aim to answer critical questions surrounding the practical applicability of graphene and its dielectric isomorph hexagonal boron nitride as thermal materials in real devices. Specifically, the fundamental heat dissipation pathways of joule-heated graphene channels are inspected within the framework of silicon-based electronics as well as next-generation flexible electronic architectures. The study reveals that lateral heat spreading is essential to mitigating hot-spot formation. As a result, the inclusion of h-BN as a thermal interface material between the active graphene layer and the underlying support facilitates significant reductions in device operating temperatures due to enhanced lateral heat spreading. More than a passive thermal layer, an h-BN support increases the intrinsic thermal conductivity of graphene relative to other support materials based on an additional study in this work. An analytical solution of the phonon Boltzmann transport equation is derived to explain the observed phenomenon

Innovations in Graphene-Based Polymer Composites

Author : Sanjay Mavinkere Rangappa
Publisher : Woodhead Publishing
ISBN 13 : 0128237902
Total Pages : 642 pages
Book Rating : 4.1/5 (282 download)

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Book Synopsis Innovations in Graphene-Based Polymer Composites by : Sanjay Mavinkere Rangappa

Download or read book Innovations in Graphene-Based Polymer Composites written by Sanjay Mavinkere Rangappa and published by Woodhead Publishing. This book was released on 2022-06-15 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovations in Graphene-Based Polymer Composites reviews recent developments in this important field of research. The book's chapters focus on processing methods, functionalization, mechanical, electrical and thermal properties, applications and life cycle assessment. Leading researchers from industry, academia and government research institutions from across the globe have contributed to the book, making it a valuable reference resource for materials scientists, academic researchers and industrial engineers working on recent developments in the area of graphene-based materials, graphene-based polymer blends and composites. Readers will gain insights into what has been explored to-date, along with associated benefits and challenges for the future. Presents a strong emphasis on synthesis methods, functionalization, processing and properties Includes chapters on characterization, electrical conductivity and modeling and simulation Provides recent advances in applications, including drawbacks and future scope

Experimental Investigation of Thermal Transport in Low-dimensional Nanomaterials

Author : Daniel Josephus Alpas Villaroman
Publisher :
ISBN 13 :
Total Pages : 135 pages
Book Rating : 4.:/5 (11 download)

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Book Synopsis Experimental Investigation of Thermal Transport in Low-dimensional Nanomaterials by : Daniel Josephus Alpas Villaroman

Download or read book Experimental Investigation of Thermal Transport in Low-dimensional Nanomaterials written by Daniel Josephus Alpas Villaroman and published by . This book was released on 2017 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Phonon Transport at the Interfaces of Vertically Stacked Graphene and Hexagonal Boron Nitride Heterostructures

Author :
Publisher :
ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (971 download)

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Book Synopsis Phonon Transport at the Interfaces of Vertically Stacked Graphene and Hexagonal Boron Nitride Heterostructures by :

Download or read book Phonon Transport at the Interfaces of Vertically Stacked Graphene and Hexagonal Boron Nitride Heterostructures written by and published by . This book was released on 2016 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hexagonal boron nitride (h-BN) is a substrate for graphene based nano-electronic devices. We investigate the ballistic phonon transport at the interface of vertically stacked graphene and h-BN heterostructures using first principles density functional theory and atomistic Green's function simulations considering the influence of lattice stacking. We compute the frequency and wave-vector dependent transmission function and observe distinct stacking-dependent phonon transmission features for the h-BN/graphene/h-BN sandwiched systems. We find that the in-plane acoustic modes have the dominant contributions to the phonon transmission and thermal boundary conductance (TBC) for the interfaces with the carbon atom located directly on top of the boron atom (C-B matched) because of low interfacial spacing. The low interfacial spacing is a consequence of the differences in the effective atomic volume of N and B and the difference in the local electron density around N and B. For the structures with the carbon atom directly on top of the nitrogen atom (C-N matched), the spatial distance increases and the contribution of in-plane modes to the TBC decreases leading to higher contributions by out-of-plane acoustic modes. We find that the C-B matched interfaces have stronger phonon-phonon coupling than the C-N matched interfaces, which results in significantly higher TBC (more than 50%) in the C-B matched interface. The findings in this study will provide insights to understand the mechanism of phonon transport at h-BN/graphene/h-BN interfaces, to better explain the experimental observations and to engineer these interfaces to enhance heat dissipation in graphene based electronic devices.

Thermal Transport in Carbon-Based Nanomaterials

Author : Gang Zhang
Publisher : Elsevier
ISBN 13 : 0323473466
Total Pages : 386 pages
Book Rating : 4.3/5 (234 download)

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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

A First-principles Investigation of the Transition Between Two- and Three-dimensional Thermal Transport in Graphene and Graphite

Author : Patrick Strongman
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis A First-principles Investigation of the Transition Between Two- and Three-dimensional Thermal Transport in Graphene and Graphite by : Patrick Strongman

Download or read book A First-principles Investigation of the Transition Between Two- and Three-dimensional Thermal Transport in Graphene and Graphite written by Patrick Strongman and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two-dimensional materials have become a popular research area over the past two decades because of their unique physical properties. The low dimensionality of these materials leads to interesting, and useful, transport properties such as thickness-dependent band gaps and high electrical and thermal conductivity. These materials have applications in nanoelectronics, optoelectronics, and thermoelectric energy generation, the performance of which depends sensitively on understanding and controlling how heat transport occurs. Most low dimensional materials can be derived by isolating them from their bulk counterparts, which are often comprised of stacks of the two-dimensional layers that are weakly bound together. These layered bulk materials often maintain some of the two-dimensional characteristics of their monolayer form because of the weak interlayer bonds. One common example of such a "quasi-2D" material is graphite, which is made of layered carbon sheets, i.e. graphene. When going from graphite to graphene the room-temperature in-plane thermal conductivity varies from approx. 2000 W/m K to 5800 W/m K, respectively. Both values are exceptionally high, but there is still a large difference between the two. Nevertheless, the majority of studies focus either on the bulk or low-dimensional versions of materials, with little focus on how the transition from 3D to 2D influences the microscopic properties and transport characteristics. The purpose of this study was to explain how the thermal transport properties of layered materials transition between two and three dimensions. Graphene and graphite were used as simple materials to model this transition. The thermal transport properties were calculated from first-principles using density functional theory (DFT) and iterative solutions to the Boltzmann transport equation (BTE). The transition between two and three dimensions was modelled by systematically moving the layers of graphite apart from each other until they were essentially isolated graphene sheets. The converged $\kappa$ values of the limiting cases of graphite and graphene agree with experimental measurements and previous calculations, with the stretched cases showing a monotonically increasing thermal conductivity from $\kappa_{\text{graphite}}$ to $\kappa_{\text{graphene}}$. Surprisingly, the largest variation in the thermal transport properties resulted from changes in the phonon dispersion. This is contrary to the previous belief that the difference in $\kappa$ resulted from certain three-phonon selection rules in graphene, which reduce the scattering probability, and do not apply to graphite. The selection rules appear to mostly still apply to graphite and the stretched graphite cases, indicating that the primary mechanism resulting in the differences between $\kappa_{\text{graphene}}$ and $\kappa_{\text{graphite}}$ was the shape of the phonon dispersion, and a corresponding shift in the phonon DOS. This type of analysis could be applied to other layered materials in the future to identify materials with the potential to be exceptional thermal conductors.

Emerging Applications of Carbon Nanotubes and Graphene

Author : Bhanu Pratap Singh
Publisher : CRC Press
ISBN 13 : 1000838633
Total Pages : 305 pages
Book Rating : 4.0/5 (8 download)

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Book Synopsis Emerging Applications of Carbon Nanotubes and Graphene by : Bhanu Pratap Singh

Download or read book Emerging Applications of Carbon Nanotubes and Graphene written by Bhanu Pratap Singh and published by CRC Press. This book was released on 2023-02-27 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprehensively reviews recent and emerging applications of carbon nanotubes and graphene materials in a wide range of sectors. Detailed applications include structural materials, ballistic materials, energy storage and conversion, batteries, supercapacitors, smart sensors, environmental protection, nanoelectronics, optoelectronic and photovoltaics, thermoelectric, and conducting wires. It further covers human and structural health monitoring, and thermal management applications. Key selling features: Exclusively takes an application-oriented approach to cover emerging areas in carbon nanotubes and graphene Covers fundamental and applied knowledge related to carbon nanomaterials Includes advanced applications like human and structural health monitoring, smart sensors, ballistic protection and so forth Discusses novel applications such as thermoelectrics along with environmental protection related application Explores aspects of energy storage, generation and conversion including batteries, supercapacitors, and photovoltaics This book is aimed at graduate students and researchers in electrical, nanomaterials, chemistry, and other related areas.

Nano/Microscale Heat Transfer

Author : Zhuomin M. Zhang
Publisher : Springer Nature
ISBN 13 : 3030450392
Total Pages : 780 pages
Book Rating : 4.0/5 (34 download)

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Book Synopsis Nano/Microscale Heat Transfer by : Zhuomin M. Zhang

Download or read book Nano/Microscale Heat Transfer written by Zhuomin M. Zhang and published by Springer Nature. This book was released on 2020-06-23 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt: This substantially updated and augmented second edition adds over 200 pages of text covering and an array of newer developments in nanoscale thermal transport. In Nano/Microscale Heat Transfer, 2nd edition, Dr. Zhang expands his classroom-proven text to incorporate thermal conductivity spectroscopy, time-domain and frequency-domain thermoreflectance techniques, quantum size effect on specific heat, coherent phonon, minimum thermal conductivity, interface thermal conductance, thermal interface materials, 2D sheet materials and their unique thermal properties, soft materials, first-principles simulation, hyperbolic metamaterials, magnetic polaritons, and new near-field radiation experiments and numerical simulations. Informed by over 12 years use, the author’s research experience, and feedback from teaching faculty, the book has been reorganized in many sections and enriched with more examples and homework problems. Solutions for selected problems are also available to qualified faculty via a password-protected website.• Substantially updates and augments the widely adopted original edition, adding over 200 pages and many new illustrations;• Incorporates student and faculty feedback from a decade of classroom use;• Elucidates concepts explained with many examples and illustrations;• Supports student application of theory with 300 homework problems;• Maximizes reader understanding of micro/nanoscale thermophysical properties and processes and how to apply them to thermal science and engineering;• Features MATLAB codes for working with size and temperature effects on thermal conductivity, specific heat of nanostructures, thin-film optics, RCWA, and near-field radiation.

Forcefields for Atomistic-Scale Simulations: Materials and Applications

Author : Akarsh Verma
Publisher : Springer Nature
ISBN 13 : 9811930929
Total Pages : 395 pages
Book Rating : 4.8/5 (119 download)

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Book Synopsis Forcefields for Atomistic-Scale Simulations: Materials and Applications by : Akarsh Verma

Download or read book Forcefields for Atomistic-Scale Simulations: Materials and Applications written by Akarsh Verma and published by Springer Nature. This book was released on 2022-08-19 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the forcefields/interatomic potentials that are used in the atomistic-scale and molecular dynamics simulations. It covers mechanisms, salient features, formulations, important aspects and case studies of various forcefields utilized for characterizing various materials (such as nuclear materials and nanomaterials) and applications. This book gives many help to students and researchers who are studying the forcefield potentials and introduces various applications of atomistic-scale simulations to professors who are researching molecular dynamics.

Growth and Transfer of Graphene and Hexagonal Boron Nitride by Chemical Vapor Deposition

Author : Théo Levert
Publisher :
ISBN 13 :
Total Pages : 0 pages
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Book Synopsis Growth and Transfer of Graphene and Hexagonal Boron Nitride by Chemical Vapor Deposition by : Théo Levert

Download or read book Growth and Transfer of Graphene and Hexagonal Boron Nitride by Chemical Vapor Deposition written by Théo Levert and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major challenge is to find a way to grow those materials in order to achieve an easy and economically attractive way to produce large area of those materials with a good quality. Another challenge is to transfer those materials on substrate compatible with electronics (mainly SiO2). We will focus the first part of our work on investigation of the growth conditions required to produce large area graphene and h-BN of good quality and their transfer on SiO2. Flexible electronics has become an important field of research for many applications, such as flexible batteries. In this goal, several materials have been used such as PEN, PET or polyimide (PI). All these materials present a good flexibility and a chemical compatibility with microelectronics process but they suffer from poor thermal conductivity, leading to lower utilization of power of devices deposited compared to classic microelectronic substrate such as SiO2. Several way have been recently investigated to bypass this problem and a good solution is to fill the matrix of the polymer or polyimide with nanomaterials or nanofillers. We choose to use graphene and h-BN as the filler in a 3D shape: a foam of graphene or h-BN as the nanofiller and we chose a PI as the matrix. In the second part, we will explain in details how we achieve novel flexible substrates with enhanced thermal properties. We succeed in producing polycrystalline graphene on copper with quite a good quality, fully covering the metallic substrate with a size of 2x2cm. We tried to grow monocrystalline graphene using standard CVD and achieved hexagonal single crystals of 30μm, which is quite small compared to other methods used in literature. We synthetized polycrystalline h-BN using copper as a catalyst and ammonia borane as the precursor with a size of 6x2cm with a good homogeneity on all available substrate. We were able to transfer both graphene an h-BN on Si02 substrate using both classical wet transfer and bubbling transfer, leading to a fastest transfer and resulting on clean transfer of our materials, free of cracks, bubbles and resist residues. We succeed in producing both 3D graphene and 3D h-BN as foam using a Nickel foam as the catalyst, resulting in multilayer graphene and h-BN with a good quality. We produced new flexible and thermal efficient substrates using these foams as a filler in a matrix of PI, already commonly used as a classical flexible substrate for microelectronics. We developed two generations of substrates. We found similar mechanical properties and thermal stability as the commercial Kapton. We deposited thermistors on the surface in order to study the thermal dissipation of our samples. We improved the maximum power applied on the thermistors up to 100% before breakdown.