Semiconductor Electronics Materials Devices and Simple Circuits - Result Question 29
29. Application of a forward bias to a $p-n$ junction
(a) widens the depletion zone
[2005]
(b) increases the potential difference across the depletion zone
(c) increases the number of donors on the $n$ side
(d) increases the electric field in the depletion zone
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Answer:
Correct Answer: 29. (c)
Solution:
- (c)
Before diffusion
Number of donors is more because electrons from-ve terminal of the cell pushes (enters) the $n$ side and decreases the number of uncompensated pentavalent ion due to which potential barrier is reduced. The neutralised pentavalent atom are again in position to donate electrons.