High Speed Semiconductor Physics. Theoretical Approaches and Device Physics

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CHAPTER TWO, THEORIES FOR MATERIALS PROCESSING:

Material Technologies:

Materials Science and Engineering is a field of engineering that encompasses a wide spectrum of materials types. These materials span form metals, ceramics, polymers or plastics, semiconductors and composites which are material combinations. The world now is both dependent upon certain specific limited materials. Every product we see or use is made of certain materials. These ranges from cars, airplanes, computers, refrigerators, microwave ovens, TVs, dishes, silverware, athletic equipment of all types, and biomedical devices such as replacement joints and limbs. All of them are made of materials tailored for their specific application. Their specific application is fine-tuned result of a careful selection of materials and controlled manufacturing processes to convert the materials into the final engineered product. A great understanding of material properties is thus desirable.
New materials technologies developed through engineering and science continue to make startling changes in our lives in this 21st century. These engineers deal with the science and technology of producing materials that have properties and shapes suitable for practical use. Engineering activities range from primary materials production through design and development of new materials for reliable and economical final product manufacturing and such activities are found in aerospace, transportation, electronics, energy conversion and biomedical systems industries. New and improved materials are an "underpinning technology" and one that stimulate innovation and product improvement. High quality products result from improved processing and more emphasis will be placed on reclaiming and recycling. For these many reasons, most surveys name the materials field as one of the careers with excellent future opportunities.
CD-ROMs, dessert plates, basketballs, car engines, telephones, and audiocassettes are made of materials. Although the field deals with materials, it encompasses an incredible diversity of topics especially those in solid state physics and problems constituting the four elements of the field; processing, structure, properties, and performance depend on a clear understanding of material properties hence history of material science is measured by innovations made in materials. Developments in metals like iron and bronze enabled advances in civilization thousands of years ago due to a clear understanding of quantum beahviour of materials.
The synergy continues today in the fiber optics and has created the World Wide Web or in the development of biomaterials that has developed a mimic of living tissues. It is noticeable that as you explore the quantum field of materials, it is useful to be familiar with some generic categories of materials. Metals are materials that are a combination of "metallic elements" and these elements when combined have electrons that are non-localized. As a consequence, these materials have generic properties. Metals are good conductors of heat and electricity and quite strong but deformable bond and structure that tend to have a lustrous look when polished.
Ceramics are compounds between metallic and nonmetallic elements. They include compounds as oxides, nitrides, and carbides. They are insulating in nature and resistant to high temperatures as well as harsh environments. Plastics on the other hand are also known as polymers. They are organic compounds based upon carbon and hydrogen with very large molecular structures, low density and are not stable at high temperatures. Semiconductors are materials that have electrical properties intermediate between metallic conductors and ceramic insulators. Their electrical properties strongly depend upon the presence of small amounts of impurities. We also have materials we call composites that consist of more than one material type. An example is the fiberglass which is a combination of glass and a polymer. Concrete and plywood are other composites. New composites include ceramic fibers in either metal or polymer matrixes.