TC 9-62
ENERGY BANDS - groups of energy levels that result from the close proximity of
atoms in a solid. The three most important energy bands are the
CONDUCTION BAND, FORBIDDEN BAND, and VALENCE BAND.
categorized by using the energy band concept. It is the width of the forbidden
band which determines whether a material is an insulator, a semiconductor, or
a conductor. A CONDUCTOR has a very narrow forbidden band or none at
all. A SEMICONDUCTOR has a medium width forbidden band. An
INSULATOR has a wide forbidden band.
COVALENT BONDING - the sharing of valence electrons between two or more
atoms. It is this bonding that holds the atoms together in an orderly structure
called a CRYSTAL.
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TC 9-62
23 June 2005
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