Electronic Properties of Materials

Semiconductors (Electrical Properties of Materials) Part 6

Quantum Semiconductor Devices It is the ultimate goal of industry to make semiconductor switches for computer applications as small, as fast, as inexpensive, and as efficient as possible. Conventional field-effect transistors pose, ultimately, certain limitations towards progressive miniaturization: the smaller they become, the less effective they switch, owing to current leakage, and particularly because of […]

Semiconductors (Electrical Properties of Materials) Part 7

Digital Circuits and Memory Devices The reader might legitimately wonder at this point how transistors are used in computers and similar devices. Even though this topic sidetracks the flow of our presentation somewhat, a few introductory remarks on switching devices, information processing, and information storage may nevertheless be of interest. We need to start with […]

Electrical Properties of Polymers, Ceramics, Dielectrics, and Amorphous Materials Part 1

Conducting Polymers and Organic Metals Materials which are electrical (and thermal) insulators are of great technical importance and are, therefore, used in large quantities in the electronics industry, e.g., as handles for a variety of tools, as coatings for wires, or as casings for electrical equipment. Most polymeric materials have the required insulating properties and […]

Electrical Properties of Polymers, Ceramics, Dielectrics, and Amorphous Materials Part 2

Ionic Conduction In ionic crystals (such as the alkali halides), the individual lattice atoms transfer electrons between each other to form positively charged cations and negatively charged anions. The binding forces between the ions are electrostatic in nature and are thus very strong. The room-temperature conductivity of ionic crystals is about twenty-two orders of magnitude […]

Electrical Properties of Polymers, Ceramics, Dielectrics, and Amorphous Materials Part 3

Dielectric Properties Insulators (also often called dielectric materials) possess a number of additional important electrical properties that make them useful in the electronics industry. They will be explained in this section. When a voltage is momentarily applied to two parallel metal plates which are separated by a distance, L, as shown in Fig. 9.16, then […]

The Optical Constants (Optical Properties of Materials) Part 1

Introduction The most apparent properties of metals, their luster and their color, have been known to mankind since metals were known. Because of these properties, metals were already used in ancient times for mirrors and jewelry. The color was utilized 4000 years ago by the ancient Chinese as a guide to determine the composition of […]

The Optical Constants (Optical Properties of Materials) Part 2

Characteristic Penetration Depth, W, and Absorbance, a The field strength, E, is hard to measure. Thus, the intensity, I, which can be measured effortlessly with light sensitive devices (such as a photodetector, see Section 8.7.6) is commonly used. The intensity equals the square of the field strength. Thus, the damping term in (10.18) may be […]

Atomistic Theory of the Optical Properties (Optical Properties of Materials) Part 1

Survey In the preceding topic, the optical constants and their relationship to electrical constants were introduced by employing the "continuum theory." The continuum theory considers only macroscopic quantities and interrelates experimental data. No assumptions are made about the structure of matter when formulating equations. Thus, the conclusions which have been drawn from the empirical laws […]

Atomistic Theory of the Optical Properties (Optical Properties of Materials) Part 2

Free Electrons With Damping (Classical Free Electron Theory of Metals) The simple reflectivity spectrum as depicted in Fig. 11.3 is seldom found for metals. We need to refine our model. We postulate that the motion of electrons in metals is damped. More specifically, we postulate that the velocity is reduced by collisions of the electrons […]

Atomistic Theory of the Optical Properties (Optical Properties of Materials) Part 3

Bound Electrons (Classical Electron Theory of Dielectric Materials) The preceding sections have shown that the optical properties of metals can be described and calculated quite well in the low-frequency range by applying the free electron theory. We mentioned already that this theory has its limits at higher frequencies, at which we observe that light is […]

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