Difference between Conductor Semiconductor and Insulator

This article covers the key differences between Conductor, Semiconductor, and Insulator on the basis of Conductivity, Resistivity, Forbidden Gap, Conduction, Band Structure, Current Flow, Band Overlap, 0 Kelvin Behavior, and Examples. The following table covers the key Differences between Conductor Semiconductor and Insulator.

• You May Also Read: Difference between Electric and Magnetic Circuits 

Characteristics	Conductor	Semi-Conductor	Insulator
Conductivity	High	Moderate	Low
Resistivity	Low	Moderate	Very High
Forbidden gap	No forbidden gap	Small forbidden gap	Large forbidden gap
Temperature coefficient	Positive	Negative	Negative
Conduction	Large number of electrons for conduction	Very small number of electrons for conduction	Moderate number of electrons for conduction
Conductivity value	Very high $\text{1}{{\text{0}}^{\text{-7}}}\text{mho/m}$	Between those of conductors and insulators i.e. $\text{1}{{\text{0}}^{\text{-7}}}\text{mho/m}$ to $\text{1}{{\text{0}}^{\text{-13}}}\text{mho/m}$	Negligible like $\text{1}{{\text{0}}^{\text{-13}}}\text{mho/m}$
Resistivity value	Negligible; less than $\text{1}{{\text{0}}^{\text{-5}}}\text{ }\Omega \text{-m}$	Between those of conductors and insulators i.e. $\text{1}{{\text{0}}^{\text{-5}}}\text{ }\Omega \text{-m}$ to $\text{1}{{\text{0}}^{\text{5}}}\text{ }\Omega \text{-m}$	Very high; more than $\text{1}{{\text{0}}^{\text{5}}}\text{ }\Omega \text{-m}$
Band structure
Current flow	Due to free electrons	Due to free electrons and holes more than that in insulators	Due to free electrons but negligible
Number of current carriers at normal temperature	Very high	Low	Negligible
Band overlap	Both conduction and valence bands are overlapped.	Both bands are separated by an energy gap of 1.1eV	Both bands are separated by an energy gap of 6eV to 10eV
0 Kelvin Behavior	Acts like a superconductor	Acts like an insulator	Acts like an insulator
Formation	Formed by metallic bonding	Formed by covalent bonding	Formed by ionic bonding
Valence Electrons	One valence electron in the outermost shell	Four valence electron in the outermost shell	Eight valence electron in the outermost shell
Examples	Copper, mercury, aluminum, silver	Germanium, Silicon	Wood, Rubber, Mica, Paper

Difference between Conductors, Semiconductors, and Insulators on the Basis of Energy Bands

Conductor

In conductive materials, no band gaps exist so electrons move easily using a continuous, partly full conduction band.

Semiconductor

In semiconductor materials, the band gap between the conduction band and valence band is smaller and at normal temperature (room temperature), there is enough energy accessible to displace a few electrons from the valence band into the conduction band.
As temperature increases, the conductivity of a semiconductor material increases.

Insulator

In insulators, there is a large band gap between the conduction and valence band. The valence band remains full since no movement of electrons occurs and as a result, the conduction band remains empty as well.

Conductor Semiconductor and Insulator Key Takeaways

Understanding the differences between conductors, semiconductors, and insulators is crucial due to their distinct electrical properties and vital roles in various applications. Conductors, with their high conductivity and free-moving electrons, are essential in power transmission, electrical wiring, and circuit design. Semiconductors, thanks to their controlled conductivity and sensitivity to temperature and impurities, form the backbone of modern electronics—used in devices like transistors, diodes, and integrated circuits. Insulators, with their high resistivity and strong electron binding, are key in protecting devices and ensuring safety by preventing unwanted current flow. These classifications, based on factors like band structure, resistivity, and carrier behavior, form the foundation for designing and implementing efficient and reliable electrical and electronic systems across industries.