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Solid State Physics |
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The branch of Physics concerned with the structure and the properties of solids and the phenomena associated with solids. These phenomena include electrical conductivity, superconductivity, photoconductivity, photoelectric effect and field emission. These properties and the associated phenomena are often dependent on the structure of solid. On the basis of structure, solids can be divided into crystalline and non-crystalline. The crystalline state of solids is characterized by regular or periodic arrangement of the atoms or molecules. Most of the solids are crystalline in nature. This is due to the reason that the energy release during the formation of an ordered structure is more than that released during the formation of a disordered structure. The crystalline solid is the low energy state and is therefore, preferred by most solids. The crystalline solids may be subdivided into single crystals and polycrystalline solids. In single crystals, the periodicity of atoms extends throughout the material as in case of diamond, quartz etc. A polycrystalline material is an aggregate of the number of small crystallites with random orientations separated by well defined boundaries. The small crystallites are known as grains and the boundaries as grain boundaries. The non-crystalline or amorphous solids are characterized by completely random arrangement of atoms or molecules. The periodicity, if at all present, extends up to a distance of a few atomic diameters only. In other words, these solids exhibit short range order. Such types of materials are formed when the atoms do not get sufficient time to undergo a periodic arrangement. Glass is an example of amorphous solids. The properties of solids may be understood in terms of simple models of solids. These models include free electron gas model, nearly free electron gas model, Cohen-Fritzsche-Ovshinsky model etc. |
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Applets |
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Bragg's law diffraction: how waves reveal the atomic structure of atom |
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| Calculates Fermi level, n and p | |
| Simulates drift, diffusion, generation and recombination in energy band | |
| Simulates drift, diffusion, generation and recombination in real space | |
| Illustrates p-n junction electrostatics | |
| Calculates heterojunction band diagrams | |
| Compares strain layer with misfit dislocation | |
| Illustrates MOS capacitor | |
| Electron diffraction on Si | |
| Electron diffraction on GaAs | |
| Creating a silicon seaspace | |
| Creating a silicon Yin Yang | |
| PN diode fabrication | |
| Building a transistor | |
| Fabrication of n-channel MOSFET | |
| BJT-FET pair on the same chip | |
| Fabrication @ various companies | |
| Atom builder | |
| Quasiperiodic tilings | |
| Fourier transform of quasiperiodic tilings | |
| Intermolecular interaction | |
| Diffusion, drift and recombination | |
| Indirect recombination via an energy state in the band gap. | |
| Diffusion, drift and recombination | |
| Indirect recombination via an energy state in the band gap. | |
| Fermi Function and Localized Energy States | |
| Carrier Concentration vs. Fermi Level | |
| Carrier Concentration vs. Fermi Level and the Density of States | |
| Energy Band Diagram and E-k Diagram (AlGaAs) | |
| Energy Band Diagram and E-k Diagram(SiGe) | |
| Moderate-doping vs. Heavy-doping | |
Waqas Ahmed -- All rights reserved