Download or read book Thermal Transport in Semiconductors and Metals from First principles written by Ankit Jain and published by . This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Transport in Semiconductors written by Pol Torres Alvarez and published by Springer. This book was released on 2018-06-28 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Starting from a broad overview of heat transport based on the Boltzmann Transport Equation, this book presents a comprehensive analysis of heat transport in bulk and nanomaterials based on a kinetic-collective model (KCM). This has become key to understanding the field of thermal transport in semiconductors, and represents an important stride. The book describes how heat transport becomes hydrodynamic at the nanoscale, propagating very much like a viscous fluid and manifesting vorticity and friction-like behavior. It introduces a generalization of Fourier’s law including a hydrodynamic term based on collective behavior in the phonon ensemble. This approach makes it possible to describe in a unifying way recent experiments that had to resort to unphysical assumptions in order to uphold the validity of Fourier’s law, demonstrating that hydrodynamic heat transport is a pervasive type of behavior in semiconductors at reduced scales.
Download or read book First Principles Theoretical Investigation on Phonon Transport in Materials with Extreme Conductivity written by Huan Wu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced materials with extreme thermal conductivity are critically important for various technological applications including energy conversion, storage, and thermal management. High thermal conductivity is desirable for efficient heat spreading in electronics, and low thermal conductivity is needed for thermal insulation and thermoelectric energy harvesting. However, practical application deployments are usually limited by the materials availability and understanding the fundamental origins for extreme thermal conductivity remains challenging. My PhD research focuses on applying and developing first-principles computations to understand the microscopic thermal transport mechanisms of the emerging materials and to discover new materials with ultrahigh and ultralow thermal conductivity. My dissertation is composed of three themes. The first theme is focused on understanding the fundamental origins and transport mechanisms for a group of high thermal conductivity semiconductors that were discovered recently by our group. In particular, boron phosphide (BP) and boron arsenide (BAs) crystals have been synthesized and measured with thermal conductivities of 460 and 1300 W/mK respectively, representing the best thermal conductor among common bulk metals and semiconductors. I have conducted ab initio calculations based on density functional theory to investigate phonon anharmonicity, size-dependent transport from diffusive to ballistic regime, as well as the effect from defect scattering. Our study shows that, unlike the commonly accepted rule for most materials near room temperature, high-order anharmonicity through the four-phonon process is significant in BA because of its unique band structure. In addition, I have performed multiscale Monte Carlo simulations to solve phonon Boltzmann transport equations to compute heat dissipation in three-dimensional practical measurement samples and electronic devices, which quantitively determines temperature distributed resulted by non-equilibrium phonon transport and underscores the promise of our developed BP and BAs for the next generation of thermal management technologies. The second theme of my thesis is to theoretical search for new ultra-high thermal conductivity materials, with the aim to push the limit of existing materials database. We have calculated the thermal conductivity of several B-C-X ternary compounds and found the R3m-BNC2 has ultrahigh thermal conductivity at ~2200 W/mK, which is comparable with the existing highest thermal conductivity materials, diamond. We also calculate the thermal conductivity of single-layer boron compounds in III-V group, and find high thermal conductivity of single-layer h-BAs at around 400 W/K. My computational studies enable atomistic understanding through their phonon band structures, scattering spaces, lifetimes, etc. The third theme of my thesis is to investigate phonon transport in ultralow thermal conductivity materials with a focus on tin selenide (SnSe). SnSe is a recently discovered high performance thermoelectric material, but its intrinsic low thermal conductivity remains debating in recent literature. In collaboration with my labmates, we combine phonon theory and experiments to investigate phonon softening physics. In particular, my calculated phonon frequencies of SnSe under varying temperatures indicate strong phonon renormalization due to higher-order anharmonicity. The comparison of my theory results with experiments indicates that the widely used harmonic model fails to descript the phonon renormalization and thus thermal conductivity of SnSe. Instead, I have developed self-consistent phonon theory to capture the higher order interactions and provided very good agreement with the experimentally measured ultralow thermal conductivity and thermophysical properties of SnSe.
Download or read book Electrons and Phonons written by J.M. Ziman and published by Oxford University Press. This book was released on 2001-02 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a classic text of its time in condensed matter physics.
Download or read book Advanced Thermoelectrics written by Zhifeng Ren and published by CRC Press. This book was released on 2017-11-06 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview on nanostructured thermoelectric materials and devices, covering fundamental concepts, synthesis techniques, device contacts and stability, and potential applications, especially in waste heat recovery and solar energy conversion. The contents focus on thermoelectric devices made from nanomaterials with high thermoelectric efficiency for use in large scale to generate megawatts electricity. Covers the latest discoveries, methods, technologies in materials, contacts, modules, and systems for thermoelectricity. Addresses practical details of how to improve the efficiency and power output of a generator by optimizing contacts and electrical conductivity. Gives tips on how to realize a realistic and usable device or module with attention to large scale industry synthesis and product development. Prof. Zhifeng Ren is M. D. Anderson Professor in the Department of Physics and the Texas Center for Superconductivity at the University of Houston. Prof. Yucheng Lan is an associate professor in Morgan State University. Prof. Qinyong Zhang is a professor in the Center for Advanced Materials and Energy at Xihua University of China.
Download or read book Electrons and Phonons written by John M. Ziman and published by . This book was released on 1960 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Physics of Phonons written by Gyaneshwar P. Srivastava and published by Routledge. This book was released on 2019-07-16 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: There have been few books devoted to the study of phonons, a major area of condensed matter physics. The Physics of Phonons is a comprehensive theoretical discussion of the most important topics, including some topics not previously presented in book form. Although primarily theoretical in approach, the author refers to experimental results wherever possible, ensuring an ideal book for both experimental and theoretical researchers. The author begins with an introduction to crystal symmetry and continues with a discussion of lattice dynamics in the harmonic approximation, including the traditional phenomenological approach and the more recent ab initio approach, detailed for the first time in this book. A discussion of anharmonicity is followed by the theory of lattice thermal conductivity, presented at a level far beyond that available in any other book. The chapter on phonon interactions is likewise more comprehensive than any similar discussion elsewhere. The sections on phonons in superlattices, impure and mixed crystals, quasicrystals, phonon spectroscopy, Kapitza resistance, and quantum evaporation also contain material appearing in book form for the first time. The book is complemented by numerous diagrams that aid understanding and is comprehensively referenced for further study. With its unprecedented wide coverage of the field, The Physics of Phonons will be indispensable to all postgraduates, advanced undergraduates, and researchers working on condensed matter physics.
Download or read book Semiconductor Heterostructures written by Zh. I. Alferov and published by . This book was released on 1989 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of the Thermal Conductivity of Metals Alloys and Semiconductors written by John R. Madigan and published by . This book was released on 1962 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present status of the theory of thermal conductivity in solids is such that although the processes leading to thermal resistance are understood in a qualititative manner, there is, as yet no reliable quantitative theory. To illustrate the successes and failures of the present theory we have calculated the heat conduction in a perfect linear lattice. It is possible to perform the necessary calculations for this model without the dange of becoming lost in a forest of indices. In a perfect crystal of reasonable size phonon-phonon interactions are the only scattering events which determine thermal resistance and the transition probability vanishes for phonon-phonon scattering in a one-dimensional lattice. We have demonstrated that to simultaneously satisfy the selection rules on the wave vectors and the energy at least one of the wave vectors must be to a reciprocal lattice vector (more precisely zero in the one-dimensional case). This causes the transition probability as calculated by first order perturbation theory to vanish for cubic anharmonic terms in the potential energy of the lattice. The thermal conductivity of simple alloys has been calculated by assuming that the addtional scattering in the alloy is due to mass difference of the elements comprising the alloy. This "isotope effect" has been used to calculate the thermal conductivity of Si-Ge alloys.
Download or read book Thermoelectric Thin Films written by Paolo Mele and published by Springer. This book was released on 2019-07-17 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will provide readers with deep insight into the intriguing science of thermoelectric thin films. It serves as a fundamental information source on the techniques and methodologies involved in thermoelectric thin film growth, characterization and device processing. This book involves widespread contributions on several categories of thermoelectric thin films: oxides, chalcogenides, iodates, nitrides and polymers. This will serve as an invaluable resource for experts to consolidate their knowledge and will provide insight and inspiration to beginners wishing to learn about thermoelectric thin films. Provides a single-source reference on a wide spectrum of topics related to thermoelectric thin films, from organic chemistry to devices, from physical chemistry to applied physics, from synthesis to device implementation; Covers several categories of thermoelectric thin films based on different material approaches such as oxides, chalcogenides, iodates, nitrides and polymers; Discusses synthesis, characterization, and device processing of thermoelectric thin films, as well as the nanoengineering approach to tailor the properties of the used materials at the nanoscale level.
Download or read book Transport Phenomena in Micro and Nanoscale Functional Materials and Devices written by Joao B. Sousa and published by Elsevier. This book was released on 2021-03-26 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport Phenomena in Micro- and Nanoscale Functional Materials and Devices offers a pragmatic view on transport phenomena for micro- and nanoscale materials and devices, both as a research tool and as a means to implant new functions in materials. Chapters emphasize transport properties (TP) as a research tool at the micro/nano level and give an experimental view on underlying techniques. The relevance of TP is highlighted through the interplay between a micro/nanocarrier's characteristics and media characteristics: long/short-range order and disorder excitations, couplings, and in energy conversions. Later sections contain case studies on the role of transport properties in functional nanomaterials. This includes transport in thin films and nanostructures, from nanogranular films, to graphene and 2D semiconductors and spintronics, and from read heads, MRAMs and sensors, to nano-oscillators and energy conversion, from figures of merit, micro-coolers and micro-heaters, to spincaloritronics. Presents a pragmatic description of electrical transport phenomena in micro- and nanoscale materials and devices from an experimental viewpoint Provides an in-depth overview of the experimental techniques available to measure transport phenomena in micro- and nanoscale materials Features case studies to illustrate how each technique works Highlights emerging areas of interest in micro- and nanomaterial transport phenomena, including spintronics
Download or read book New Materials and Devices Enabling 5G Applications and Beyond written by Nadine Collaert and published by Elsevier. This book was released on 2024-01-24 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: New Materials and Devices for 5G Applications and Beyond focuses on the materials, device architectures and enabling integration schemes for 5G applications and emerging technologies. It gives a comprehensive overview of the trade-offs, challenges and unique properties of novel upcoming technologies. Starting from the application side and its requirements, the book examines different technologies under consideration for the different functions, both more conventional to exploratory, and within this context the book provides guidance to the reader on how to possibly optimize the system for a particular application. This book aims at guiding the reader through the technologies required to enable 5G applications, with the main focus on mm-wave frequencies, up to THz. New Materials and Devises for 5G Applications and Beyond is suitable for industrial researchers and development engineers, and researchers in materials science, device engineering and circuit design. Reviews challenges and emerging opportunities for materials, devices, and integration to enable 5G technologies Includes discussion of technologies such as RF-MEMs, RF FINFETs, and transistors based on current and emerging materials (InP, GaN, etc.) Focuses on mm-wave frequencies up to the terahertz regime
Download or read book Thermal Energy written by Yatish T. Shah and published by CRC Press. This book was released on 2018-01-12 with total page 1112 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book details sources of thermal energy, methods of capture, and applications. It describes the basics of thermal energy, including measuring thermal energy, laws of thermodynamics that govern its use and transformation, modes of thermal energy, conventional processes, devices and materials, and the methods by which it is transferred. It covers 8 sources of thermal energy: combustion, fusion (solar) fission (nuclear), geothermal, microwave, plasma, waste heat, and thermal energy storage. In each case, the methods of production and capture and its uses are described in detail. It also discusses novel processes and devices used to improve transfer and transformation processes.
Download or read book Thermal Management of Gallium Nitride Electronics written by Marko Tadjer and published by Woodhead Publishing. This book was released on 2022-07-13 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Management of Gallium Nitride Electronics outlines the technical approaches undertaken by leaders in the community, the challenges they have faced, and the resulting advances in the field. This book serves as a one-stop reference for compound semiconductor device researchers tasked with solving this engineering challenge for future material systems based on ultra-wide bandgap semiconductors. A number of perspectives are included, such as the growth methods of nanocrystalline diamond, the materials integration of polycrystalline diamond through wafer bonding, and the new physics of thermal transport across heterogeneous interfaces. Over the past 10 years, the book's authors have performed pioneering experiments in the integration of nanocrystalline diamond capping layers into the fabrication process of compound semiconductor devices. Significant research efforts of integrating diamond and GaN have been reported by a number of groups since then, thus resulting in active thermal management options that do not necessarily lead to performance derating to avoid self-heating during radio frequency or power switching operation of these devices. Self-heating refers to the increased channel temperature caused by increased energy transfer from electrons to the lattice at high power. This book chronicles those breakthroughs. Includes the fundamentals of thermal management of wide-bandgap semiconductors, with historical context, a review of common heating issues, thermal transport physics, and characterization methods Reviews the latest strategies to overcome heating issues through materials modeling, growth and device design strategies Touches on emerging, real-world applications for thermal management strategies in power electronics
Download or read book Out of the Crystal Maze written by Lillian Hoddeson and published by Oxford University Press, USA. This book was released on 1992 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focuses on the field of solid-state physics - also referred to as condensed matter physics - which grew to maturity between 1920 and 1960. The history of some exciting developments is told here in an easy-to-follow text, accessible to general readers, while maintaining standards of high scholarship.
Download or read book Electron Theory of Metals written by I. M. Lifshits and published by Springer. This book was released on 2013-05-14 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It took us a long time to write this book. In 1959, two of us (Lifshits and Kaganov) pub lished a review of the mechanics of electrons with a complex dispersion law. About that time, geometrical terms such as extremal sections, curvatures, diameters, limiting points began to appear in papers on the electron theory of metals. They were followed by terms quite unusual in the scientific literature: monsters, pockets, arms, sheets, and so on. With their excitingly shaped figures, papers on the electron theory of metals began to resemble catalogs of exhibitions of abstract or ultramodern sculpture. The modern theory of metals was passing through its romantic period. Each newly interpreted Fermi surface and each discovery of a new structure sensitive phenomenon was an emotional experience for the authors and readers alike. The atti tude of the theoreticians was epitomized by phrases such as "This method or this phenomenon can be used to reconstruct the Fermi surface . . . ," which were found at the end of almost every paper on the electron theory of metals. The experimentalists selected convenient meth ods, being guided not so much by the elegance of a particular method as by its experimental capabilities. Gradually, the romantic approach gave way to a systematic activity, which re sulted in the interpretation of the energy spectra of the majority of metals. There were some unavoidable disappointments.
Download or read book Multi carrier Coupling and Hot Carrier Dynamics at Interfaces and Surfaces written by Yijun Ge and published by . This book was released on 2022 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Electrons are the major heat carriers in metals, as are phonons in semiconductors. The role of spin waves (magnons) in thermal transport problems has attracted attention in recent years with the discovery of spin Seebeck effects (SSE) in spintronics. Interactions among these particles or excitations are the origin of many fascinating phenomena and the focus of this work. Despite the computational cost, first-principles calculations use fewer approximations and no fitting parameters in comparison to semi-classical methods; therefore they produce more reliable results. Chapter 1 considers the theory of electron-electron, electron-phonon and phonon-magnon couplings from first principles. Chapter 2 reports first-principles calculations of electron-phonon coupling in bilayer graphene and the corresponding contribution to carrier scattering. At the phonon [gamma] point, electrons with energies less than 200 meV are scattered predominantly by LA' and TA' modes while higher- energy electron scattering is dominated by optical phonon modes. Based on a two-temperature model, heat transfer from electrons with an initial temperature of 2000 K to the lattice (phonons) with an initial temperature of 300 K is computed, and in the overall relaxation process, most of this energy scatters into K-point phonon optical modes due to their strong coupling with electrons and their high energies. A Drude model is used to calculate photoconductivity for bilayer graphene with different doping levels. Good agreement with prior experimental trends for both the real and imaginary components of photoconductivity confirms the model's applicability. The effects of doping levels and electron-phonon scattering on photoconductiviy are analyzed. We also extract acoustic and optical deformation potentials from average scattering rates obtained from density functional theory (DFT) calculations and compare associated photoconductivity calculations with DFT results. The comparison indicates that momentum-dependent electron-phonon scattering potentials are required to provide accurate predictions. Chapter 3 combines first-principles calculations, spin-lattice dynamics and the non-equilibrium Green's function (NEGF) method to compute thermal boundary conductance at a three-dimensional Co-Cu interface, considering spin-lattice interactions. Spin-lattice interactions are quantified through exchange interactions between spins, and the exchange constants are obtained from first principles. Equilibrium molecular dynamics (EMD) is used to calculate heat flux across the interface after the spin and lattice subsystems are in equilibrium. Because of the weak interaction between Co and Cu layers adjacent to the interface, spin-wave transmission is low. Spins are scattered by phonons inside the Co contact, and interfacial thermal conductance is reduced. We also compare the results to the NEGF method. Phonon and magnon scattering rates are incorporated into Buttiker probes attached to the device. NEGF results exhibit a similar trend in thermal boudary conductance with spins included. The Green's function is solved recursively; therefore it can be applied to large devices. Chapter 4 investigates electronic and optical properties of single layer and bilayer armchair graphene nanoribbons using the first-principles method. An increase of nanoribbon width reduces the band gap and causes a redshift in photon absorption energy. We find that the 3n + 2 family nanoribbons have the smallest band gaps and lowest onset photon absorption energy among all three families considered due to the most [pi]-conjugation indicated by the exciton wavefunctions. We also compare the bilayer [alpha] and [beta] alignments of armchair graphene nanoribbons with their single-layer counterparts.The extra layer of these nanoribbons reduces the band gap and the onset photon absorption energy, and the difference between the [alpha] alignment and the single-layer configuration is more significant than that of the [beta] alignment and the single layer. Our calculations indicate that the optical properties of graphene nanoribbons depend on the details of atomic structures, including nanoribbon width, edge alignment, and number of layers. Chapter 5 investigates the photo-thermal effect in the methane decomposition process. By calculating electronic transitions in polycyclic aromatic hydrocarbons from TDDFT, we extract the absorption coefficients. Further, the absorption coefficients are mapped to the experimental light intensity profile to predict the total absorption spectra. Temperature rise can be further induced by calculating heat capacities of the polycyclic aromatic hydrocarbons using frequencies of the vibrational modes.
