The conductivity refers to the ability of a material or substance to freely pass electric current. The conductivity of a material depends fundamentally on its atomic and molecular structure. For instance: Cadmium, Boron, Aluminum, Barium.
A material is conductive when, when it comes into contact with an electrically charged body, electricity is transmitted to all points on its surface. A conductive material offers little resistance to the passage of electricity. Electrons can freely circulate through it because they are loosely bound to atoms and therefore can conduct electricity. The best electrical conductors are metals.
Although all materials allow the conduction of electric current to some degree, those who do it best are recognized as conductors, while, on the contrary, materials that do not let electricity pass through will be insulating.
A material is semiconductor when it behaves either as a conductor or as an insulator, depending on the electric field in which it is found. It is not as good a conductor as metal, but it is not an insulator.
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. They differ from the intrinsic semiconductor because they contain a small percentage of impurities (trivalent or pentavalent elements). A certain alteration can be introduced to the crystalline molecular structure of silicon or germanium so that they allow the passage of electric current in only one direction. The process of applying impurities is called “doping.”
- Type N semiconductor. Doping material is added to increase the amount of free electrons, allowing the conduction of electrical charge. However, the N-type semiconductor is not as good a conductor as a conductive metal body.
- P-type semiconductor. Instead of adding doping material that increases the number of electrons, trivalent atoms or impurities are added to the material that, when joined to the semiconductor atoms, create holes (the lack of an electron). Thus, the material becomes conductive with a positive charge.
In order for a semiconductor to have higher conductivity, in addition to administering doping, its temperature can be raised.
Applications of semiconductor materials
Semiconductor materials have made it possible to create devices that replaced electronic tubes, generating a revolution in telecommunications due to its smaller size, the reduction of energy that its use implied and the decrease in cost.
The most important application for semiconductor materials is diodes. These electrical elements have the function of converting alternating current into direct current, a process known as rectification. Diodes are also used in solar panels, which convert solar energy into electrical energy, and as LED light emitters.
- You may be interested in: Superconductor
Examples of semiconductors
Elements:
- Cadmium (metal)
- Boron (metalloid)
- Aluminum (metal)
- Gallium (metal)
- Indian (metal)
- Germanium (metalloid)
- Silicon (metalloid)
- Phosphorus (not metal)
- Arsenic (metalloid)
- Antimony (metalloid)
- Sulfur (not metal)
- Selenium (not metal)
- Tellurium (metalloid)
Organic:
- Anthracene
- Naphthalene
- Phthalocyanines
- Polynuclear hydrocarbons
- Polymers