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Author: Mr. Elah Bozorg-Grayeli Publisher: ISBN: Category : Languages : en Pages :
Book Description
Ultrafast thermoreflectance is a powerful technique designed to measure thermal properties in films less than a micrometer thick. Careful sample design and control over the measurement timescale allow spatial and temporal confinement of the measurement to a region of interest. This work explores the capability of nanosecond and picosecond thermoreflectance in capturing the thermal properties of a host of exotic materials used in next generation electronic devices. These include the phase change material Ge2Sb2Te5 (GST), diamond substrates for high electron mobility transistors (HEMT), and multilayer Mo/Si mirrors for extreme ultraviolet wavelengths (EUV). Nanosecond and picosecond thermoreflectance were used to determine the thermal properties of the phase change material, GST, along with several candidate electrode films (C, Ti, TiN, W, and WNx) and novel electrode multilayers (C-TiN and W-WNx). These results offer a material selection roadmap for device designers seeking to tune the thermal properties of their PCM cell. This work also reports picosecond thermoreflectance measurements of GST films sandwiched between TiN electrode layers and annealed at multiple temperatures. Thermal conductivity of the hexagonal close-packed (HCP) phase exceeds that of the face centered cubic (FCC) phase due to the addition of electron thermal conduction. Electron interface transport is shown to be negligible, implying that the addition of electrons as energy carriers does not significantly affect thermal boundary resistance (TBR). Thermal spreading analysis of a representative HEMT structure on diamond and SiC substrates shows that a device-substrate thermal interface resistance in excess of 20 m2 K GW-1 negates the benefits of diamond as a substrate material. Picosecond thermoreflectance measurements on multiple diamond samples were performed to determine the thermal conductivity, thermal anisotropy, and boundary resistance of diamond on AlN substrates. Further measurements on the top and bottom surfaces of a suspended diamond films demonstrated the thermal conductivity of the coalescence region (80 W m-1 K-1) and high quality layer (1350 W m-1 K-1) of a single diamond film. Using a two-layer model of the diamond film, we predict the thickness of the coalescence region and show it to be less than 1 [micrometer]. The operating temperatures of Mo/Si multilayers used in EUV lithography affect their lifetimes. Predicting the mirror/mask damage threshold fluence requires accurate knowledge of the mirror thermal properties. This study reports high temperature thermal properties of the TaN masking film, the MoSi2 intermetallic, and the room temperature properties of the Mo/Si multilayer. The thickness dependent electrical conductivity of TaN estimates the mean free path of electrons in the film unhindered by the material interfaces (~ 30 nm). Measurements on MoSi2 demonstrate the change in thermal conductivity due to crystallization, from 1.7 W m-1 K-1 in the amorphous phase to 2.8 W m-1 K-1 in the crystalline phase. Mo/Si results demonstrate thermal conductivity (1.1 W m-1 K-1) significantly lower than previous literature assumptions (4-5 W m-1 K-1). A finite element thermal model uses these results to predict the maximum EUV fluence allowed on a Mo/Si mirror for a single shot and for a one billion pulse lifetime before causing a reflectance loss of 1%.
Author: Mr. Elah Bozorg-Grayeli Publisher: ISBN: Category : Languages : en Pages :
Book Description
Ultrafast thermoreflectance is a powerful technique designed to measure thermal properties in films less than a micrometer thick. Careful sample design and control over the measurement timescale allow spatial and temporal confinement of the measurement to a region of interest. This work explores the capability of nanosecond and picosecond thermoreflectance in capturing the thermal properties of a host of exotic materials used in next generation electronic devices. These include the phase change material Ge2Sb2Te5 (GST), diamond substrates for high electron mobility transistors (HEMT), and multilayer Mo/Si mirrors for extreme ultraviolet wavelengths (EUV). Nanosecond and picosecond thermoreflectance were used to determine the thermal properties of the phase change material, GST, along with several candidate electrode films (C, Ti, TiN, W, and WNx) and novel electrode multilayers (C-TiN and W-WNx). These results offer a material selection roadmap for device designers seeking to tune the thermal properties of their PCM cell. This work also reports picosecond thermoreflectance measurements of GST films sandwiched between TiN electrode layers and annealed at multiple temperatures. Thermal conductivity of the hexagonal close-packed (HCP) phase exceeds that of the face centered cubic (FCC) phase due to the addition of electron thermal conduction. Electron interface transport is shown to be negligible, implying that the addition of electrons as energy carriers does not significantly affect thermal boundary resistance (TBR). Thermal spreading analysis of a representative HEMT structure on diamond and SiC substrates shows that a device-substrate thermal interface resistance in excess of 20 m2 K GW-1 negates the benefits of diamond as a substrate material. Picosecond thermoreflectance measurements on multiple diamond samples were performed to determine the thermal conductivity, thermal anisotropy, and boundary resistance of diamond on AlN substrates. Further measurements on the top and bottom surfaces of a suspended diamond films demonstrated the thermal conductivity of the coalescence region (80 W m-1 K-1) and high quality layer (1350 W m-1 K-1) of a single diamond film. Using a two-layer model of the diamond film, we predict the thickness of the coalescence region and show it to be less than 1 [micrometer]. The operating temperatures of Mo/Si multilayers used in EUV lithography affect their lifetimes. Predicting the mirror/mask damage threshold fluence requires accurate knowledge of the mirror thermal properties. This study reports high temperature thermal properties of the TaN masking film, the MoSi2 intermetallic, and the room temperature properties of the Mo/Si multilayer. The thickness dependent electrical conductivity of TaN estimates the mean free path of electrons in the film unhindered by the material interfaces (~ 30 nm). Measurements on MoSi2 demonstrate the change in thermal conductivity due to crystallization, from 1.7 W m-1 K-1 in the amorphous phase to 2.8 W m-1 K-1 in the crystalline phase. Mo/Si results demonstrate thermal conductivity (1.1 W m-1 K-1) significantly lower than previous literature assumptions (4-5 W m-1 K-1). A finite element thermal model uses these results to predict the maximum EUV fluence allowed on a Mo/Si mirror for a single shot and for a one billion pulse lifetime before causing a reflectance loss of 1%.
Author: Publisher: Academic Press ISBN: 9780123751799 Category : Technology & Engineering Languages : en Pages : 560
Book Description
With the increasing demand for smaller, faster, and more highly integrated optical and electronic devices, as well as extremely sensitive detectors for biomedical and environmental applications, a field called nano-optics or nano-photonics/electronics is emerging – studying the many promising optical properties of nanostructures. Like nanotechnology itself, it is a rapidly evolving and changing field – but because of strong research activity in optical communication and related devices, combined with the intensive work on nanotechnology, nano-optics is shaping up fast to be a field with a promising future. This book serves as a one-stop review of modern nano-optical/photonic and nano-electronic techniques, applications, and developments. Provides overview of the field of Nano-optics/photonics and electronics, detailing practical examples of photonic technology in a wide range of applications Discusses photonic systems and devices with mathematical rigor precise enough for design purposes A one-stop review of modern nano-optical/photonic and nano-electronic techniques, applications, and developments.
Author: Alexander Block Publisher: ISBN: Category : Languages : en Pages : 124
Book Description
Heat transport in solids is one of the oldest problems in physics, dating back to the earliest formulations of thermodynamics. The classical laws of heat conduction are valid as long as the observed time and length scales are larger than the relaxation time and mean free path of the underlying microscopic heat carriers, such as electrons and phonons. With the advent of ultrafast lasers and nanoscale systems these regimes can now be surpassed and new refined models of heat transport are needed. In particular, the interaction of ultrashort light pulses with matter can excite electrons to high temperatures, leading to a local non-equilibrium of electrons and phonons. Under these conditions, also the transport properties of the carriers are altered.So far, these effects have typically been studied in the time domain. The cooling of photo-excited hot electrons has been studied both in metals as well as novel 2D materials, such as graphene. However, due to a lack of spatio-temporal resolution, it has not been possible to distinguish the effects of hot-electron diffusion from other cooling mechanisms, such as electron-phonon coupling.In this thesis, I directly track such ultrafast heat and carrier diffusion in space and time with ultrafast microscopy. By using the recently developed technique of probe-beam-scanning transient-absorption microscopy on thin gold films I directly resolve, for the first time, a transition from hot-electron diffusion to phonon-limited diffusion on the picosecond timescale. I support the understanding of these complex dynamics by theoretical modeling of the thermo-optical response based on a two-temperature model.I apply the same technique to study hot carrier diffusion in atomically thin monolayer graphene. By comparing differently prepared samples, I study the strong influence of external parameters, such as production type, substrate, and environment on carrier diffusion. Finally, I study hot carrier diffusion in exfoliated and encapsulated graphene devices with a novel technique of ultrafast spatio-temporal photocurrent microscopy based on the photothermoelectric effect. I extract diffusion dynamics for electrically characterized samples with the help of theoretical spatio-temporal modeling, thereby testing the fundamental relationship between electrical and thermal carrier transport.The precise quantification of ultrafast and nanoscale carrier transport with these state-of-the-art techniques leads to a broader understanding of non-equilibrium dynamics and could ultimately help the design, optimization, and heat management of the next generation of ultra-compact (opto-) electronic devices, such as solar cells, photodetectors, or integrated circuits.
Author: Xinwei Wang Publisher: John Wiley & Sons ISBN: 1118310233 Category : Technology & Engineering Languages : en Pages : 278
Book Description
This book covers the new technologies on micro/nanoscale thermal characterization developed in the Micro/Nanoscale Thermal Science Laboratory led by Dr. Xinwei Wang. Five new non-contact and non-destructive technologies are introduced: optical heating and electrical sensing technique, transient electro-thermal technique, transient photo-electro-thermal technique, pulsed laser-assisted thermal relaxation technique, and steady-state electro-Raman-thermal technique. These techniques feature significantly improved ease of implementation, super signal-to-noise ratio, and have the capacity of measuring the thermal conductivity/diffusivity of various one-dimensional structures from dielectric, semiconductive, to metallic materials.
Author: S. C. Singh Publisher: John Wiley & Sons ISBN: 3527646841 Category : Technology & Engineering Languages : en Pages : 793
Book Description
The first in-depth treatment of the synthesis, processing, and characterization of nanomaterials using lasers, ranging from fundamentals to the latest research results, this handy reference is divided into two main sections. After introducing the concepts of lasers, nanomaterials, nanoarchitectures and laser-material interactions in the first three chapters, the book goes on to discuss the synthesis of various nanomaterials in vacuum, gas and liquids. The second half discusses various nanomaterial characterization techniques involving lasers, from Raman and photoluminescence spectroscopies to light dynamic scattering, laser spectroscopy and such unusual techniques as laser photo acoustic, fluorescence correlation spectroscopy, ultrafast dynamics and laser-induced thermal pulses. The specialist authors adopt a practical approach throughout, with an emphasis on experiments, set-up, and results. Each chapter begins with an introduction and is uniform in covering the basic approaches, experimental setups, and dependencies of the particular method on different parameters, providing sufficient theory and modeling to understand the principles behind the techniques.
Author: Lichang Wang Publisher: BoD – Books on Demand ISBN: 9535104438 Category : Mathematics Languages : en Pages : 440
Book Description
Molecular Dynamics is a two-volume compendium of the ever-growing applications of molecular dynamics simulations to solve a wider range of scientific and engineering challenges. The contents illustrate the rapid progress on molecular dynamics simulations in many fields of science and technology, such as nanotechnology, energy research, and biology, due to the advances of new dynamics theories and the extraordinary power of today's computers. This first book begins with a general description of underlying theories of molecular dynamics simulations and provides extensive coverage of molecular dynamics simulations in nanotechnology and energy. Coverage of this book includes: Recent advances of molecular dynamics theory Formation and evolution of nanoparticles of up to 106 atoms Diffusion and dissociation of gas and liquid molecules on silicon, metal, or metal organic frameworks Conductivity of ionic species in solid oxides Ion solvation in liquid mixtures Nuclear structures
Author: Xiaoping Hong Publisher: ISBN: Category : Languages : en Pages : 85
Book Description
Recent advances in material science and fabrication techniques enabled development of nanoscale applications and devices with superior performances and high degree of integration. Exotic physics also emerges at nanoscale where confinement of electrons and phonons leads to drastically different behavior from those in the bulk materials. It is therefore rewarding and interesting to investigate and understand material properties at the nanoscale. Optical spectroscopy, one of the most versatile techniques for studying material properties and light-matter interactions, can provide new insights into the nanomaterials. In this thesis, I explore advanced laser spectroscopic techniques to probe a variety of different nanoscale phenomena. A powerful tool in nanoscience and engineering is scanning tunneling microscopy (STM). Its capability in atomic resolution imaging and spectroscopy unveiled the mystical quantum world of atoms and molecules. However identification of molecular species under investigation is one of the limiting functionalities of the STM. To address this need, we take advantage of the molecular `fingerprints' - vibrational spectroscopy, by combining an infrared light sources with scanning tunneling microscopy. In order to map out sharp molecular resonances, an infrared continuous wave broadly tunable optical parametric oscillator was developed with mode-hop free fine tuning capabilities. We then combine this laser with STM by shooting the beam onto the STM substrate with sub-monolayer diamondoids deposition. Thermal expansion of the substrate is detected by the ultrasensitive tunneling current when infrared frequency is tuned across the molecular vibrational range. Molecular vibrational spectroscopy could be obtained by recording the thermal expansion as a function of the excitation wavelength. Another interesting field of the nanoscience is carbon nanotube, an ideal model of one dimensional physics and applications. Due to the small light absorption with nanometer size, individual carbon nanotube is not visible under any conventional microscopy and characterization of individual nanotube becomes a focused research interest. Although electron microscopies and optical spectroscopies are developed previously to study carbon nanotubes, none of them permitted versatile imaging and spectroscopy of individual nanotube in a non-invasive, high throughput and ambient way. In this thesis a new polarization-based optical microscopy and spectroscopy is developed with exceedingly better contrast for one dimensional nano-materials and capability of individual carbon nanotube imaging and spectroscopy. This development provides a reliable way to measure the absolute absorption cross-section of individual chirality-defined carbon nanotubes. It also enables fast profiling for growth optimization and in situ characterization for functioning carbon nanotube devices. Two dimensional systems constitute another important family of nanomaterials, ranging from semi-metal (graphene), semiconductors (transition metal dichalcogenides) to insulators (h-BN). Despite of their scientific significance, they present a complete set of 2D building blocks for two dimensional electronics and optoelectronics. Heterostructures purely made of 2D thin films hold great promises due to functionality, scalability and ultrathin nature. Understanding the properties of the coupled heterolayers will be important and intriguing for these applications. With the advanced ultrafast laser spectroscopy, we study the dynamics of charge transfer process in two dimensional atomically thin semiconductors heterostructures. An extremely efficient charge transfer process is identified in atomically thin MoS2/WS2 system, which is expected to form a type-II heterojunction. Our discovery would greatly facilitate further studies of 2D materials as a photovoltaic device.
Author: Zhuomin M. Zhang Publisher: Springer Nature ISBN: 3030450392 Category : Science Languages : en Pages : 780
Book Description
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.
Author: Joao B. Sousa Publisher: Elsevier ISBN: 0323460976 Category : Science Languages : en Pages : 484
Book Description
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
Author: I. M. Mahbubul Publisher: William Andrew ISBN: 012813299X Category : Science Languages : en Pages : 375
Book Description
Preparation, Characterization, Properties and Application of Nanofluid begins with an introduction of colloidal systems and their relation to nanofluid. Special emphasis on the preparation of stable nanofluid and the impact of ultrasonication power on nanofluid preparation is also included, as are characterization and stability measurement techniques. Other topics of note in the book include the thermophysical properties of nanofluids as thermal conductivity, viscosity, and density and specific heat, including the figure of merit of properties. In addition, different parameters, like particle type, size, concentration, liquid type and temperature are discussed based on experimental results, along with a variety of other important topics. The available model and correlations used for nanofluid property calculation are also included. Provides readers with tactics on nanofluid preparation methods, including how to improve their stability Explores the effect of preparation method and stability on thermophysical and rheological properties of nanofluids Assesses the available model and correlations used for nanofluid property calculation
Author: Mr. Elah Bozorg-Grayeli
Author: Mr. Elah Bozorg-Grayeli
Author: 
Author: Alexander Block
Author: Xinwei Wang
Author: S. C. Singh
Author: Lichang Wang
Author: Xiaoping Hong
Author: Zhuomin M. Zhang
Author: Joao B. Sousa
Author: I. M. Mahbubul