Semiconductor And An Extrinsic Semiconductor

A semiconductor is the essential concept of science, on which the operations of core systems like microprocessors and microcontrollers are depended on. Depending on the efficiency of the conductivity, materials are classified as conductors, semiconductors, and insulators.

The resistance of the material decreases as the temperature increases.

A semiconductor is a material whose electrical conductivity lies between the conductor and an insulator. The semiconductor has unique characteristics like allowing the flow of current in one direction easily. It displays variable resistance and is sensitive to light or heat. A diode is a perfect example of semiconductor, which clearly displays the features of the semiconductor device. Other important semiconductor devices are op-amps, capacitors, transistors, and resistors.

Some of the best semiconductors are Silicon, Boron, Sulfur, Selenium, Germanium, Tellurium, Antimony, Carbon, Arsenic and more. Out of all these semiconductors, silicon is the most widely used component in manufacturing electronic devices.

There are two types of semiconductors

  • Extrinsic Semiconductors
  • Intrinsic Semiconductors

Extrinsic Semiconductor

A semiconductor to which an impurity is added at a controlled rate during the process of manufacturing to make it conductive is known as an extrinsic semiconductor.

There are 2 types of extrinsic semiconductor classified on the basis of the doping material added.

  • N-type semiconductors
  • P-type semiconductors

An Extrinsic semiconductor doped with electron donor atoms is referred to as N-type semiconductor due to the presence of negative electrons in the majority.

An extrinsic semiconductor doped with electron acceptor atoms is called a P-type semiconductor, due to the presence of positive holes in the majority.

Intrinsic Semiconductor

The semiconductor material which does not have any impurities is known as an intrinsic semiconductor. It is also known as pure semiconductors. Example: a pure crystalline form of Silicon and Germanium.

Free electrons in the conduction band and the holes in the valence band are exactly equal and are comparatively small. The electrical conductivity of intrinsic semiconductors are usually low and hence the conductivity is increased by a process called doping.

The process of adding impurities to a semiconductor is known as doping. The impurity added is referred to as a dopant and the amount of dopant added to an intrinsic (pure) semiconductor is directly proportional to the conductivity of the semiconductor.

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