Abstract: The chapter discusses the optical properties of semiconductors, which are characterized by electron mobilities and free carrier densities that are greater than those of insulators but less than those of both good conductors (metals) and semimetals. They have an electronic energy gap which is a nonzero difference in energy between the highest occupied states and the lowest unfilled states in an electronic band structure. The behavior of electrons in a semiconductor is examined by both real and wave vector spaces. In semiconductors at low temperatures, there are few (intrinsic) electrons in a conduction band. Consequently, if the incident light has a frequency lower than the bandgap frequency, then there is no optical absorption. When the optical frequency is above the bandgap frequency, electronic interband transitions are possible and absorption is high. Thus, semiconductors act as low pass filters, pass light below the bandgap frequency and strongly absorb the light above the bandgap frequency.
Publication Year: 2000
Publication Date: 2000-01-01
Language: en
Type: book-chapter
Indexed In: ['crossref']
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Cited By Count: 49
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