How diode is formed?[ Forward biased - Reversed biased ]

How diode is formed?

  A diode is a circuit component, which is used to control current flow through a circuit.

Diode:

  Works on the principle of doping semiconductor materials (such as silicon)

to create P and N-type semiconductors 

• When a P-type material and an N-type material are placed in close contact, a PN junction is formed.
• This separation of charges develops a potential across the depletion region, preventing further diffusion of carriers across the junction.
• This potential, known as the potential barrier, is about 0.6-0.7 Volts in a typical silicon p-n junction.

Ideal Diode - Forward Biased:

• Applied voltage reduces the barrier field.
• Holes and electrons are pushed toward the junction and the depletion zone shrinks in size.
• Carriers are swept across the junction and the depletion zone.
• There is a net carrier flow in both P and N sides = current flow.

Ideal Diode - Reversed Biased:

• Applied voltage adds to the barrier field.
• Holes and electrons are pulled toward the terminals, increasing the size of the depletion zone.
• The depletion zone becomes, in effect, an insulator for majority carriers.
• Only a very small current can flow, due to a small number of minority carriers randomly crossing D (which = reverse saturation current).