PNjunktjon

PNjunktjon is a term that refers to a semiconductor device. It is formed by the interface of a p-type semiconductor and an n-type semiconductor. In a p-type semiconductor, the majority charge carriers are holes, which are positively charged vacancies in the crystal lattice. In an n-type semiconductor, the majority charge carriers are electrons, which are negatively charged subatomic particles.

When a p-type and an n-type semiconductor are brought into contact, a region called the depletion region forms at the junction. This region is depleted of free charge carriers due to diffusion and recombination. The formation of the depletion region creates an internal electric field, known as the built-in potential.

The behavior of a PN junction is dependent on the applied voltage. When a forward bias voltage is applied, the external voltage opposes the built-in potential, reducing the width of the depletion region and allowing current to flow easily. When a reverse bias voltage is applied, the external voltage aids the built-in potential, widening the depletion region and significantly restricting current flow. This rectifying property, the ability to conduct current in one direction but not the other, is the fundamental principle behind many semiconductor devices. Diodes, transistors, and integrated circuits all rely on the properties of PN junctions.