PN-Junction Diode:

Introduction:

An electronic device which is made by linking together P-type semi-conductor and N-type semiconductor is known as p-n junction diode or a semiconductor diode. It permits the current to flow in one direction only.

Construction:

1.  A p-n junction diode or a semiconductor diode is fabricated by adding a pentavalent impurity (antimony) at the one end and a trivalent impurity (Boron or Indium) at the other end of a germanium crystal.

2. A junction is formed because of the flow of electrons n-type and p-type material and holes from p-types to n-types material and a junction is created which is p-n Junction.

3. The barrier is setup at the junction which stops further flow of free electrons from n-type to p-type and holes from p-type to n-type material.

4. The barrier is known as the junction barrier or potential barrier (0.1 - 0.7 V). The region of potential barrier is known as depletion region.

5. When p-n junction diode is linked to an external voltage source, it permits current to flow in one direction only.