Classification of Solids on the basis of Energy Bands


Classification of Solids on the basis of Energy Bands


Conducting materials are those in which number of free electrons are available for electric conduction.  In terms of energy bands, it means that electrical conductors are those which have overlapping valence and conduction bands.


In fact, there is no physical distinction between the two bands. Hence, the availability of large number of conduction electrons.

A conductor has a positive temperature coefficient of resistance.


A semiconductor material is one whose resistivity lie in between those of insulators and conductors. Examples are : silicon and germanium. In terms of energy bands, semiconducting materials can be defined as those materials which has almost an empty conduction band and almost filled valance band with a very narrow energy gap separating the two.

When an external field or temperature is applied to the semiconductor, width of the forbidden energy bands is decreased so that some of the electrons are liberated into the conduction band. In other words we can say that, conductivity of semiconductors increases with increases with temperature.

A Semiconductor has a negative temperature coefficient of resistance.


Insulators are those materials in which valence electrons are bound very tightly to their parent atoms, thus requiring very large electric field to remove them from attraction of their nuclei. Insulators have an empty conduction band. The energy gap between the valence and conduction bands is very large.


An insulator has a  negative temperature coefficient of resistance.

About the author

APSEEE administrator

2 Comments so far

Baseball CapPosted on2:06 am - Jan 1, 2020

Normally I do not learn post on blogs, however I would like to
say that this write-up very compelled me to try and do so!

Your writing style has been amazed me. Thank you, very great post.

buy cbd oilPosted on3:46 am - Mar 16, 2020

Hey very nice blog!

Leave a Reply