Basics of Semiconductor

The basics of semiconductors include the definition of semiconductor, types of semiconductor, materials used, and the properties. Let’s try to understand what is semiconductor before understanding their types.

What is semiconductor?

A semiconductor is defined as a substance with the resistivity which lies between the conductors and insulators. The electrical properties of the semiconductor lie between conductor and insulator. The number of electrons in semiconductors is very few as the atoms are grouped closely forming a crystal lattice. 

What is the classification of semiconductor?

Following is the classification of semiconductor:

  • Semiconductor 
    • Intrinsic semiconductor which is also known as pure semiconductor
    • Extrinsic semiconductor which is also known as impure semiconductor
      • P-type semiconductor:  The semiconductor mainly carries holes which is deficient of an electron. The charge of the hole is positive, which is equal and opposite to the charge of an electron. The flow of charge is in the opposite direction of electron.
      • N-type semiconductor: The semiconductor mainly carries electrons which is negative in charge. 

What are the properties exhibited by the semiconductors?

Following are the properties exhibited by the semiconductors:

  • The resistivity of semiconductor is less than an insulator but more than the conductor.
  • The temperature coefficient of the semiconductor is negative.
  • The resistance of semiconductor increases with increase in temperature and reverse with the temperature.
  • When a suitable metallic impurity is added to the semiconductor the conducting property of the semiconductor changes.

What are semiconductor materials?

For the making of the semiconductor, different types of materials are used. The primary requirement is that the material should neither be a good conductor of electricity nor a bad conductor of electricity. 

Following are the semiconductor materials:

  • Carbon
  • Silicon 
  • Boron 
  • Antimony 
  • Germanium 
  • Arsenic 
  • Selenium 
  • Silicon carbide
  • Oxides of metals
  • Sulfur 

Summary of n-type semiconductor.

  • The donors of n-type semiconductor are positively charged.
  • The availability of free electrons in the n-type semiconductor is more.
  • By doping antimony, positively charged donors are obtained, and negatively charged free electrons are obtained.

Summary of p-type semiconductor

  • The donors of p-type semiconductor are negatively charged.
  • The number of holes present in the p-type semiconductor is more.
  • By doping boron, negatively charged acceptors are obtained and positively charged holes are obtained.

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