Comparison between Conductors, Semiconductors and Insulators

Comparison between Conductors, Semiconductors and Insulators can be done in aspects like conductivity variation, conductivity order, electrical resistivity, temperature coefficient, change in temperature, energy bands and current carriers are represented below in tabular form.

1 Conductivity variation Conductivity decreases with increase in temperature up to nearly zero value. conductivity increases with increases in temperature. Conductivity is particularly sensitive to impurity type and consent. Conductivities increases with increase in temperature.
2 Conductivity order  Conductivity of metals is of the order of 107 (Ω-m)-1 Conductivity of semiconductors range from 10-6 to 104 (Ω-m)-1. The conductivity of insulators ranges between 10-10 to 10-20 (Ω-m)-1.
3 Electrical resistivity Electrical resistivity is very low and ranges from 10-9 to 10-4 (Ω-m). Resistivity is normally high and ranges between 10-3 to 103 (Ω-m). Resistivity is very high and ranges between 104 to 1017 (Ω-m).
4 Temperature coefficient Temperature coefficient of resistance is not constant. The temperature coefficient of resistance is negative. Negative resistance temperature coefficient. Probably with the rise in temperature some electrons reach to the conduction band.
5 Property with temperature variation At low temperatures they exhibit semiconductivity. At very low temperatures, some elements and their alloys exhibit infinite conductivity, i.e. superconductivity. At low temperature, semiconductors become dielectrics (insulators). No change in properties of the insulated observed.
6 Energy bands Have unfilled overlapping energy bands. Have filled energy bands and small forbidden zones. There is a large energy gap in between valence and conduction band.
7 Current carriers Current carriers in conductors are free electrons which exist whether the external field is applied or not. Current carriers are originated due to absorption of electrical, radiant or thermal energy from the external source. Electrons and holes, both serve as current carriers. The energy required for electrons to cross the energy gap between conduction band and valence band is very large and hence no conduction.

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