The major difference between conductor, insulator and semiconductor is defined by the flow of charged particles under the influence of electric field. When any voltage is applied to the conductor, electric charged particles easily flow from valence band to conduction band. Thus conductor is a good conductor of electricity. A semiconductor allows very low charge particles to move from valence band to conduction band. In insulators, there is no flow of charge particles under the influence of electric field hence insulators are the bad conductor of electricity.
Some other differences between conductor, insulator and semiconductor are explained below:
Content: Conductor Vs Insulator Vs Semiconductor
Comparison Chart
| Basis For Comparison | Conductor | Insulator | Semiconductor |
|---|---|---|---|
| Definition. | The elements which allow the flow of electric current through it by the application of voltage. | The elements which do not allow any flow of electric charge. | The elements whose conductivity lies between insulators and conductors. |
| Electric Conductivity. | Good conductor. | Bad conductor. | At 0K works , it works as an insulator while by applying thermal agitation or by adding impurity becomes good conductor. |
| Examples. | Copper, Mercury, Silver, Al, Water, Acids, Human Body, Metallic Salt, Charcoal. | Wood, Rubber, Glass, Ebonite, Mica, Sulphur, Dry air. | Germanium, Silicon, Cotton, Wool, Marble, Sand, Paper, Ivory, Moist air. |
| Energy Band. | Conduction band and valence band overlap each other. | Conduction band and valence band are separated by 6eV. | Conduction band and valence band separated by 1eV. |
| Temperature Coefficient. | Positive temperature Coefficient of resistance. | Negative Temperature Coefficient of resistance. | Negative Temperature Coefficient of resistance. |
| Charge carriers. | Electrons. | They do not contain any charge carriers. | Intrinsic charge carriers are holes and electrons. |
| Current Flow. | Current flow due to electrons. | Current does not flow. | Current flow due to holes and electrons. |
| Number of Charge Carriers. | Very High. | Negligible. | Low. |
| Valence band and conduction Band. | Valence band and conduction band is completely filled. | Valence Band is completely filled and conduction band is completely empty. | Valence band is partially empty and conduction band is partially filled. |
| Effect of temperature on conductivity. | Conductivity decreases. | Conductivity Increases. | Conductivity Increases. |
| On Increasing Temperature. | The number of current carriers decreases. | The number of current carriers increases. | The number of current carriers increases. |
| Effect of doping. | Resistance Increases. | Resistance remain unchanged. | Resistance Decreases. |
| Current Flow under the influence of electric field. | Takes place easily. | Does not take place. | Very Slow. |
| Behaviour at Absolute 0K temperature. | Behaves like super conductor. | Behaves like an Insulator. | Behaves like an Insulator. |
| Bonding Types. | Ionic bond. | Ionic Bond and Covalent Bond. | Covalent Bond. |
Definition of Conductor
Conductors are material which conduct electricity. In conductors, the ionic bond is formed between the atoms. This ionic bond causes an easy flow of charge carriers under the influence of any thermal agitation. Hence they are a good conductor of electricity. The overlapping of the valence band and conduction band allows the easy flow of electrons through them. There is no Fermi level between the valence band and the conduction band. When the small voltage is applied, the conductor will result in a large amount of current.
The current flows because of the electrons.The movement of electrons in the metal is called as electric current. Conductors are having a positive temperature coefficient of resistance. Hence as the temperature increases resistivity increases which in turn decreases the conductivity. The resistivity of the conductor is given as 10-8Ohm/cm.
Examples of Conductors are metals like Iron, Aluminium, Silver, Gold.
Definition of Insulator
Insulators are the material which do not allow any flow of electric current through them. The valence band and conduction band are separated by the energy band gap of 6eV. Thus electrons do not move from valence band to conduction band under the influence of any thermal agitation. The bond between the atoms is the covalent bond and ionic bond. The electron holds the atom very tightly and does not permit electron flow. The temperature coefficient of resistance is negative for insulators. The resistivity is given by 1012Ohm/cm.
Examples of Insulators are Wood, Rubber, Plastic.
Definition of Semiconductor
Semiconductors are the material whose conductivity lies between insulators and conductors. At absolute zero temperature, the semiconductor behaves like an insulator whereas by providing thermal agitation, the charge carriers start moving from valence band to conduction band. The valence band and conduction band are separated by the energy band gap of nearly 1eV. The bonding between atoms is the covalent bond.
The semiconductor can be classified as an intrinsic and extrinsic semiconductor. The intrinsic semiconductor is the pure form of the semiconductor. The process of adding impurities to the intrinsic semiconductor is called doping. After doping intrinsic semiconductor behaves as an extrinsic semiconductor, and becomes good conductor of electricity.
The current flow because of the movement of electrons and holes.The holes flow opposite to the direction of electrons flow. Semiconductors are having a negative temperature coefficient of resistance. Hence the resistivity decreases with the increase of temperature which in turn increases the conductivity. The resistivity is given by 10-4Ohm/cm to 103Ohm/cm.
Examples of Semiconductor are Si, Ge the energy band gap for Si=.7eV while for Ge=1.1eV.
Key Differences Between Conductor, Insulator and Semiconductor
- In conductors, the valence band and conduction band overlapped each other thus under the influence of electric field the charge carriers easily move to the conduction band, and this results into easily flow of current. In Insulators the energy gap is very high, there is no flow of electric charge, whereas in the semiconductor the valence band and the conduction band is separated by very less eV thus charge carrier flow is very less, and current will be very less.
- The flow of charge carriers decides the material, if the charge carriers flow easily under the influence of electric field, then they are called as a conductor, the material in which charge carriers do not flow easily then they are called as insulators while the material whose conductivity lies between conductor and insulators are called as a semiconductor.
- In conductors, the valence band and conduction band are nearly close to each other thus energy gap Eg=0, In insulators the energy band gap is very high given by Eg=6eV whereas in semiconductor Fermi level lies between the valence band and conduction band, the valence band and conduction band are separated by energy gap of 0.1eV.
- In the case of conductors, resistance depends on the temperature thus resistivity increases with temperature hence having a positive temperature coefficient of the resistance, which is inversely proportional to the conductivity thus conductivity decreases, while insulators are having negative temperature coefficient of resistance similar to insulator semiconductor is also having negative temperature coefficient of resistance hence increases conductivity.
- In the conductor, current flows because of negatively charged carriers called as electrons. In Insulator there is no flow of charge particles, In semiconductor the current flow because of the movement of holes and electrons, if semiconductor gains energy either because of thermal agitation or by doping then the electrons can easily move from valence band to conduction band which left behind the vacant position in the valence band which is acquired by the another electron which in turn leaves behind a vacancy, this vacancy in the valence band is positively charged called as hole. The direction of holes flow is opposite to the direction of electrons flow.
- In conductors the current flow because of electrons, therefore the charge carriers is very high, for insulators, there is no free charge carrier, In a semiconductor, the number of charge carriers is very less.
- By providing temperature to the conductor, the number of charge carriers decreases while for insulator and semiconductor the charge carriers increases.
- By adding an impurity to the conductor the resistance increases which in turn decreases the conductivity. In insulators there is no effect of adding the impurity to them, whereas semiconductor is classified as intrinsic semiconductor and extrinsic semiconductor. The pure form of the semiconductor is intrinsic semiconductor which has high resistivity, when the impurity is added to the intrinsic semiconductor then extrinsic semiconductor is obtained which is further classified as n-type semiconductor and a p-type semiconductor. The resistance of semiconductor decreases by adding an impurity to it.
- At absolute zero temperature conductors behave like superconductors, Superconductors are materials which do not contain any resistivity and conduct electricity as there is no resistivity hence having infinite conductivity without losing any energy. At absolute zero temperature, insulator and semiconductor behaves like an Insulator.
- The conductor has an ionic bond between the atoms. An Ionic bond is formed by two oppositely charged ions. The oppositely charged particles are obtained by the transfer of valence electron between atoms. In Insulator the bond formation is either an ionic bond or a covalent bond. In a semiconductor, there is covalent bond exists between the atoms this covalent bond is formed by sharing of electrons between them.
Conclusion
The crucial difference between conductor, insulator and semiconductor is that the conductivity of semiconductor lies between the conductivity of insulator and conductor.
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