A p-n junction is formed by combining p-type and n-type semiconductors, where the p-region is doped with trivalent impurities (creating holes as majority carriers) and the n-region is doped with pentavalent impurities (providing free electrons as majority carriers). Upon formation, free electrons from the n-region diffuse into the p-region, leading to the creation of a depletion region devoid of charge carriers. This region establishes a potential barrier that prevents further diffusion of charge carriers. The characteristics of a p-n junction include its behavior under forward and reverse bias conditions, where it allows current to flow easily in the forward direction while blocking it in the reverse direction until breakdown occurs, making it a fundamental building block in various electronic devices
What is a p-n junction?
A p-n junction is formed when a p-type semiconductor, doped with trivalent impurities, is joined with an n-type semiconductor, doped with pentavalent impurities, creating a region with distinct electrical properties.
What are the majority charge carriers in a p-type semiconductor?
The majority charge carriers in a p-type semiconductor are holes, which are created by the absence of electrons due to the trivalent doping.
What happens when a p-n junction is formed?
When a p-n junction is formed, free electrons from the n-region diffuse into the p-region, leading to the creation of a depletion region where charge carriers are absent.
What is the potential barrier in a p-n junction?
The potential barrier is the voltage difference that develops across the depletion region, preventing further diffusion of charge carriers; it is typically about 0.7 V for silicon and 0.3 V for germanium.
How does a p-n junction behave under forward bias?
Under forward bias, the p-side is connected to a positive voltage and the n-side to a negative voltage, allowing current to flow easily across the junction as the potential barrier is overcome.
What type of charge carriers are majority carriers in a p-type semiconductor?
a) Electrons
b) Holes
c) Ions
d) Neutrons
Answer: b) Holes
What is formed when a p-type semiconductor is joined with an n-type semiconductor?
a) Metal junction
b) p-n junction
c) Schottky junction
d) Ohmic junction
Answer: b) p-n junction
What is the potential barrier voltage for silicon in a p-n junction?
a) 0.1 V
b) 0.3 V
c) 0.7 V
d) 1.0 V
Answer: c) 0.7 V
What happens to the depletion region when a p-n junction is forward biased?
a) It widens
b) It narrows
c) It disappears
d) It remains unchanged
Answer: It narrows
In which biasing condition does a p-n junction allow current to flow easily?
a) Reverse bias
b) Forward bias
c) Zero bias
d) Breakdown bias
Answer: b) Forward bias