chemistry

Semiconductor materials

The 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 in 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 hinders the presence of free electrons.

Material is a 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 insulating. Under certain conditions, the conductive elements allow the circulation of electric current in a single direction.

See also: Examples of Conductors and Insulators

Types of semiconductor materials

  • 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 in that it contains a small percentage of impurities (trivalent or pentavalent element). 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.”
  • Semiconductor type N: Doping material is added to increase the number 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.
  • P-type semiconductor: Instead of adding doping material that increases the number of electrons, trivalent atoms or impurities are added to the material, which, 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 greater conductivity, in addition to administering doping, it can be raised in temperature or increased in illumination.

Features

  • Rectify alternating current: by joining n and p-type semiconductors, the electronic imbalance (between electrons and holes) creates a voltage.
  • Detect radio signals.
  • Amplify electric current signals.
  • Bipolar Junction Transistors – Switches or amplifiers that operate 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: pressure allows conductivity to increase.

 

See also: What is a superconductor?

Examples of semiconductors

Elements :

  1. Cadmium: Metal.
  2. Boron: Metalloid
  3. Aluminum: Metal
  4. Gallium: Metal
  5. Indian: Metal
  6. Germanium: Metalloid
  7. Silicon: Metalloid
  8. Phosphor:  No metal
  9. Arsenic: Metalloid
  10. Antimony: Metalloid
  11. Sulfur:  No metal
  12. Selenium: No metal
  13. Tellurium: Metalloid

Organic :

  1. Anthracene
  2. Naphthalene
  3. Phthalocyanines
  4. Polynuclear hydrocarbons
  5. Polymers

Related links:

  • Examples of Drivers
  •  Examples of Insulators
  •  Examples of Superconductors

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