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Question
In the depletion region of a diode ______.
- there are no mobile charges.
- equal number of holes and electrons exist, making the region neutral.
- recombination of holes and electrons has taken place.
- immobile charged ions exist.
Options
a and b
a, b and d
c and d
a, b, c and d
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Solution
a, b, c and d
Explanation:
On account of the difference in concentration of charge carrier in the two sections of the P-N junction, the electrons from N-region diffuse through the junction into P-region and the hole from P-region diffuse into N-region.
Due to diffusion, the neutrality of both N and P-type semiconductor is disturbed, a layer of negatively charged ions appear near the junction in the P-crystal and a layer of positive ions appears near the junction in N-crystal. This layer is called the depletion layer.
The thickness of the depletion layer is 1 micron = 10-6 m.
Width of depletion layer ∞ 1/Dopping
Depletion is directly proportional to temperature.
Important point: The P-N junction diode is equivalent to the capacitor in which the depletion layer acts as a dielectric.
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