Which causes the barrier layer in a PN junction?

Which causes the barrier layer in a PN junction?

Right Answer is:



  • When a P-N junction is formed, the holes in the P-region diffuse into N-region and the electrons in the N-region diffuse into P-region. This process is called diffusion which happens for a short time as soon as the P-N junction is formed.
  • After a few combinations of holes and electrons, a restraining force is developed which is known as the potential barrier.
  • The potential difference created across the p-n junction due to the diffusion of electrons and holes is called the potential barrier. 

  • This potential barrier prevents further diffusion of holes and electrons. The barrier force development can be easily explained. That is, each recombination of hole and electron eliminates hole and electron.
  • Recombination causes the barrier layer in a PN junction. During this process, the negative acceptor ions in the P-region and positive donor ions in the N-region are left uncompensated.
  • The additional holes trying to diffuse into N-region and additional electrons trying to diffuse into P-region are repelled by these negative and positive charges respectively.
  • The region containing this uncompensated acceptor and donor ions is called the depletion layer.
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