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gracy
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valence band and conduction band overlap in conductors but not in semiconductors and insulators why?t
ok i have one more questionDrDu said:Well, full bands give no contribution to conductivity, so if all bands are either full or empty, you get an insulator. To get a metal, (i.e. non-zero conductivity) some band has to be occupied only partially. Overlap of valence and conduction band is but one possibility. In this case, both valence and conduction band will contribute to conductivity. The other possibility is that the conduction band is not completely filled, without this being due to an overlap with the valence band.
Semiconductors are materials that have electrical conductivity between that of an insulator and a conductor. They are widely used in electronic devices such as computers, phones, and solar cells.
The valence band in semiconductors is the highest energy band that is fully occupied by electrons at absolute zero temperature. It is responsible for the electrical and optical properties of the material.
The energy band structure of semiconductors determines their conductivity. The larger the band gap between the valence and conduction bands, the lower the conductivity. This is because electrons require more energy to jump from the valence band to the conduction band and become free to conduct electricity.
The valence band is the highest energy band that is fully occupied by electrons at absolute zero temperature, while the conduction band is the next highest energy band that is empty at absolute zero. Electrons in the conduction band are free to move and conduct electricity.
Impurities can introduce extra energy levels within the band gap of semiconductors, creating new energy levels for electrons to occupy. This can change the conductivity of the material and make it either more conductive (n-type) or less conductive (p-type).