Crystals in semiconductors

Gallliumphosphide (GaP) is a light-colored highly pure crystal form used as whiskers and crystals in semiconductor devices. 

Recall from Figure 6.2 that the gap between the valence and conduction bands called the band gap. Eg, can be used to classify materials as conductors, insulators, or semiconductors also recall that for semiconductors the value of Eg is typically on the order of 1-2 eV. The magnitude of the band gap is characteristic of the lattice alone and varies widely for different crystals. In semiconductors, the valence and conduction bands do not overlap as in metals, but there are enough electrons in the valence band that can be promoted to the conduction band at a certain temperature to allow for limited electrical conduction. For example, in silicon, the energies of the valence electrons that bind the crystal together lie in the valence band. All four... 

The books we are presenting deal with various aspects of chemical bonding in crystals, particularly in semiconductor crystals. In semiconductors, the nature of the chemical bonds can vary within wide limits and extend over a considerable part of the well-known tetrahedron of the metallic, covalent, ionic, and van der Waals types of chemical bond. This tetrahedron is only approximate but it provides a sufficiently clear basis for the classification of transitions which may occur between different types of bond. 

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See also in sourсe #XX -- [ ]

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