Test: The P-N Junction - Electrical Engineering (EE) MCQ

In a P-N junction, the p-region is doped with acceptor impurities, resulting in a higher concentration of holes (positive charge carriers) compared to the n-region. The n-region, conversely, has a higher concentration of electrons (negative charge carriers).

This difference in majority charge carriers is fundamental to the operation of semiconductor devices.

Donor impurities denote an electron to the n-type material making it a electron majority carrier & vice-versa.

 Holes are the majority charge carriers in p-type material & vice-versa.

In an n-type material, electrons are the majority charge carriers, whereas in a p-type material, holes are the majority charge carriers.

• The n-region has a greater concentration of electrons compared to the p-region.
• The p-region primarily has holes as its majority carriers.

A p-n junction diode is a two-terminal device, consisting of an anode and a cathode. Therefore, the statement that diodes have three terminals is false.

In a p-n junction, minority charge carriers refer to the less abundant charge carriers in each region. Specifically:

• In the p-region (p-type material):
  • Electrons are the minority charge carriers because holes are the majority due to doping with trivalent impurities.
• In the n-region (n-type material):
  • Holes are the minority charge carriers since electrons dominate from pentavalent doping.

Thus:

• Electrons are the minority in the p-region.
• Holes are the minority in the n-region.

A Schottky diode is a type of semiconductor device known for its fast switching and low forward voltage drop. It is primarily characterised by the following features:

• Metal-semiconductor junction: Unlike regular diodes, Schottky diodes are formed by a junction between a metal and a semiconductor, typically silicon.
• Low forward voltage drop: This characteristic allows for efficient operation, making them suitable for high-speed applications.
• Fast switching speeds: Schottky diodes can switch on and off much quicker than standard diodes, which is beneficial in high-frequency circuits.
• Applications: They are commonly used in power supplies, radio frequency applications, and as rectifiers in solar panels.

When p & n region come together diffusion takes places & a depletion region is established with opposite charges on both the sides of the junction.

A potential difference is established across the junctions due to recombination of holes & electrons. This growing field (barrier potential) stops the further diffusion.

The diode is forward biased, positive is connected to p & vice-versa, as such batter provides EMF to drive electrons from n-region to p-region.