Conductivity refers to the ability of a material or substance to let freely pass the electric current. The conductivity of a material depends on its atomic and molecular structure.
A material is conductive when, when coming into contact with a body charged with electricity, electricity is transmitted to all points on its surface. The best electrical conductors are metals.
A material is insulating when it has low electrical conductivity. This is due to the potential barrier that exists between the valence bands and conduction, which makes the presence of free electrons difficult.
A material is semiconductor when it behaves either as a conductor or as an insulator, depending on the electric field in which it is located. It is not as good a conductor as a metal, but it is not insulating. Under certain conditions the conductive elements allow the circulation of electric current in a single direction.
See also: 30 Examples of Conductors and Insulators
Table of Contents
Types of semiconductors according to their purity
- Intrinsic semiconductors : When a material is an intrinsic semiconductor, it is capable of transmitting electricity in its pure state, that is, without impurities or other atoms in its structure.
- Extrinsic semiconductors : It differs from the intrinsic semiconductor because it contains a small percentage of impurities (trivalent or pentavalent element). A certain alteration can be introduced into the crystalline molecular structure of silicon or germanium to allow the passage of electrical current in only one direction. The process of applying impurities is called “doping”.
- Semiconductor type N : Dopant material is added to increase the amount of free electrons, thus allowing the conduction of the electric charge. However, the N-type semiconductor is not as good a conductor as a conductive metal body.
- Semiconductor type P : Instead of adding dopant material that increases the amount of electrons, trivalent atoms or impurities are added to the material that, when they join the semiconductor atoms, create gaps (the lack of an electron). Thus, the material becomes conductive with positive charge.
In order for a semiconductor to have greater conductivity, in addition to administering doping, the temperature can be raised or the illumination can be increased.
Functions
- Rectify the alternating current: uniting semiconductors of type n and p, the electronic imbalance (between electrons and holes) creates a voltage.
- Detect radio signals.
- Amplify electrical current signals.
- Bipolar junction transistors: switches or amplifiers that work in central computer processing units.
- Field effect transistors: they are used to store information (they are the memory of computers ).
- Thermistors: temperature sensors .
- Pressure transducers: the pressure allows the conductivity to increase.
Examples of semiconductors
Elements :
- Cadmium: Metal.
- Boron: Metalloid
- Aluminum: Metal
- Gallium: Metal
- Indian: Metal
- Germanium: Metalloid
- Silicon: Metalloid
- Phosphorus: No metal
- Arsenic: Metalloid
- Antimony: Metalloid
- Sulfur: No metal
- Selenium: No metal
- Tellurium: Metalloid
Organic :
- Anthracene
- Naphthalene
- Phthalocyanines
- Polynuclear hydrocarbons
- Polymers
