Forbidden Band

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forbidden band

[fər¦bid·ən ′band]
(solid-state physics)
A range of unallowed energy levels for an electron in a solid.

Forbidden Band


a region of values of energy that electrons in an ideal crystal (without defects) cannot have. In semiconductors the forbidden band separating the valence band and the conduction band is usually considered. In this case the energy difference between the lower level (bottom) of the conduction band and the upper level (ceiling) of the valence band is called the width of the forbidden band.

References in periodicals archive ?
Now, a member of that research group, Francisco Meseguer of the Polytechnic University of Valencia in Spain, reports that the scientists have created a structure of rods in air that stops sound in the forbidden band from every angle.
Initial results show that this structure has a number of unexpected features, including an extra forbidden band.
In such a case the allowed and forbidden bands are clearly separated.
The quadrupole interaction is a just theoretical artifact so far, he admits, but it explains the appearance of forbidden bands arising in a great number of experiments on symmetrical molecules with surface enhanced Raman scattering (SERS).