Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

Gallium oxide (Ga2O3) is emerging as a viable candidate for certain classes of power electronics, solar blind UV photodetectors, solar cells, and sensors with capabilities beyond existing technologies due to its large bandgap. It is usually reported that there are five different polymorphs of Ga2O3, namely, the monoclinic (β-Ga2O3), rhombohedral (α), defective spinel (γ), cubic (δ), or orthorhombic (e) structures. Of these, the β-polymorph is the stable form under normal conditions and has been the most widely studied and utilized. Since melt growth techniques can be used to grow bulk crystals of β-GaO3, the cost of producing larger area, uniform substrates is potentially lower compared to the vapor growth techniques used to manufacture bulk crystals of GaN and SiC. The performance of technologically important high voltage rectifiers and enhancement-mode Metal-Oxide Field Effect Transistors benefit from the larger critical electric field of β-Ga2O3 relative to either SiC or GaN. However, the absence of clear demonstrations of p-type doping in Ga2O3, which may be a fundamental issue resulting from the band structure, makes it very difficult to simultaneously achieve low turn-on voltages and ultra-high breakdown. The purpose of this review is to summarize recent advances in the growth, processing, and device performance of the most widely studied polymorph, β-Ga2O3. The role of defects and impurities on the transport and optical properties of bulk, epitaxial, and nanostructures material, the difficulty in p-type doping, and the development of processing techniques like etching, contact formation, dielectrics for gate formation, and passivation are discussed. Areas where continued development is needed to fully exploit the properties of Ga2O3 are identified.

A review of Ga2O3 materials, processing, and devices

International Technology Roadmap for Semiconductors 2003の要求清浄度について － シリコンウエハ表面と雰囲気環境に要求される清浄度, 分析方法の現状について －

Small, light weight and multifunctional electronic components are attracting much attention because of the rapid growth of the wireless communication systems and microwave products in the consumer electronic market. The component manufacturers are thus forced to search for new advanced integration, packaging and interconnection technologies. One solution is the low temperature cofired ceramic (LTCC) technology enabling fabrication of three-dimensional ceramic modules with low dielectric loss and embedded silver electrodes. During the past 15 years, a large number of new dielectric LTCCs for high frequency applications have been developed. About 1000 papers were published and ∼500 patents were filed in the area of LTCC and related technologies. However, the data of these several very useful materials are scattered. The main purpose of this review is to bring the data and science of these materials together, which will be of immense help to researchers and technologists all over the world. The comme...

Low loss dielectric materials for LTCC applications: a review

Heat transfer - A review of 1996 literature

Plasma display panels (PDPs) are a leading technology for large size television displays. Screen inefficiencies result in considerable localized heat generation within the PDP and necessitate aggressive thermal management to reduce spatial temperature variations across the screen. In the current study, experimental and numerical techniques were used to investigate the effect of a natural graphite heat spreader on hot spots and the temperature distribution across the screen. A commercial, 42 inch high-definition PDP, retrofitted with natural graphite heat spreaders with in-plane thermal conductivity varying from 140 to 440 W/mK and thicknesses varying from 0.5 mm to 1.4 mm, served as the test vehicle for this study. Infrared thermography was used to obtain a thermal map of the entire screen for different illumination patterns for each spreader configuration. Using a luminance meter, the luminosity of a selected point on the screen has been measured. A three-dimensional numerical model of this typical PDP, including the glass and spreader layers, as well as the chassis electronics, has been developed and the numerically obtained temperature distributions were compared to the experimental data

The Impact of a Thermal Spreader on the Temperature Distribution in a Plasma Display Panel

The majority of today's leading-edge notebook computers relies on heat pipes for internal spreading and use forced convection, with micro-fans, to reject heat to the ambient. Such techniques have worked efficiently in the relatively flat form factor of these computers, but may not be capable of providing high heat flux cooling in ever shrinking volumes. Moreover, the power limitations of portable computers, as well as growing concern for the environment, make it desirable that the requisite thermal management be accomplished with a minimum expenditure of energy. It is, thus, essential that the developers of such notebook computers follow a rigorous design methodology and achieve an optimal design for energy and space savings. This paper illustrates a "top down" thermal design methodology aimed at achieving energy efficient thermal management in a compact notebook computer, while satisfying the requirements for highly integrated design. The paper begins with a review of the passive cooling limits, and uses analytic models to determine the thermal performance that can be attained in a standard notebook form factor. Numerical modeling, along with additional analysis, is used to design the optimum compact active cooling system for both for space and energy efficiency.

Energy efficient cooling of notebook computers

This book encompasses a broad area of microand opto-electronic engineering materials: their physics, mechanics, reliability, and packaging, with an emphasis on physical design issues and problems. The editors tried to bring in the most eminent engineers and scientists as chapter authors and put together the most comprehensive book ever written on the subjects of materials, mechanics, physics, packaging, functional performance, mechanical reliability, environmental durability and other aspects of reliability of microand opto-electronic assemblies, components, devices, and systems. University professors and leading industrial engineers contributed to the book. The contents of the book reflect the state-of-the-art in the above listed fields of applied science and engineering. The intended audience are all those who work in microand opto-electronics, and photonics; electronic and optical materials; applied and industrial physics; mechanical and reliability engineering; electron and optical devices and systems. The expected and targeted readers are practitioners and professionals, scientists and researchers, lecturers and continuing education course directors, graduate and undergraduate students, technical supervisors and entrepreneurs. The book can serve, to a great extent, as an encyclopedia in the field of physics and mechanics of microand opto-electronic materials and structures. In the editors’ opinion, it can serve also as a textbook, as a reference book, and as a guidance for selfand continuing education, i.e., as a source of comprehensive and in-depth information in its areas. The book’s chapters contain both the description of the state-of-the-art in a particular field, as well as new results obtained by the chapter authors and their colleagues. We would like to point out that many methods and approaches addressed in this book extend far beyond microelectronics and photonics. Although these methods and approaches were developed, advanced and reported primarily in application to microand opto-electronic systems, they are applicable also in many related areas of engineering and physics. The editors are proud of the broad scope of the book, and of the quality of the contributed chapters, and would like to take this opportunity to deeply acknowledge, with thanks, the conscientious effort of the numerous contributors.

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Thermo-Optic Effects in Polymer Bragg Gratings

Forced flow of refrigerants and dielectric liquids, undergoing phase change in a microgap channel above an active chip is a promising candidate for the thermal management of advanced semiconductor devices. This paper presents two-phase heat transfer and pressure drop results for a chip-scale, uniformly heated, microgap channel using HFE-7100 and FC-87 as the working fluids. Results for two channel configurations are presented: a chip-size, short channel, representative of a product configuration and a longer channel, representing a laboratory prototype. Each microgap channel was tested with three nominal gap heights: 100, 200, and 500 micrometer.

Avram Bar-Cohen

Papers

Heat transfer - A review of 1996 literature

The Impact of a Thermal Spreader on the Temperature Distribution in a Plasma Display Panel

Energy efficient cooling of notebook computers

Thermo-Optic Effects in Polymer Bragg Gratings

Two-phase microgap cooling of a thermally-simulated microprocessor chip