Differences between Semi conductor and Insulator (Semi conductor vs Insulator)

A semi conductor is a solid substance that has electrical conductivity between a conductor and an insulator. This property makes it suitable for the control of electric current. 

A insulator is a substance that does not allow the flow of electric current. Diamond, mica, glass and wood are insulators.

Semi Conductor vs Insulator

Semi Conductor	Insulator
Under some conditions, semiconductors allow the flow of electric current and at some other conditions will not conduct electricity. Conductivity is moderate  between a conductor and an insulator	Insulator does not allow the flow of electric current. Current will not flow even when potential difference  is applied across them
Semi conductors  has low number of free electrons	Insulators do not contain free electrons or negligible free electrons
The conductivity is based on the free electrons and holes	No conductivity due to the absence of free electrons
More energy or potential difference is needed to remove the outer electron in the atom in a semi conductor	The outer electron in the atom cannot be removed with potential difference applied
In semi-conductor, conductivity increases with increase in temperature as the number of free  electrons increases with rise in temperature	Generally conductivity increases with rise in temperature as the electrons will go to the upper band. The availability of free electrons in the conduction band increases conductivity.
Semi conductor has resistivity lying between a conductor and an insulator	High resistivity
Resistivity decreases with increase in temperature	Resistivity decreases with increase in temperature
They have negative coefficient of resistance	They have negative coefficient of resistance
In semi conductors, the energy gap is small, at room temperature, some electrons has the energy to jump the gap and enter the conduction band	The energy gap is very large In insulators, the valence band is completely filled and conduction band is empty
The energy gap is small. It is more than conductors and less than insulators	Generally conductivity increases with rise in temperature as the electrons will go to the upper band. The availability of free electrons in the conduction band increases conductivity.
Pure semi-conductors become insulators at absolute zero (0 K) as there are no free electrons.	Rise in temperature lead to rise in number of free electrons thereby increases conductivity
Mixing of impurities causes decrease in resistance and increase in conductivity	No change in resistance and conductivity
Example of Semi conductor: Silicon, Germanium, Gallium	Example of Insulator: wood, plastic, glass, diamond

*The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance.