Question: Q. 13. (i) How is a photodiode fabricated?
(ii) Briefly explain its working. Draw its $I-V$ characteristics for two different intensities of illumination. U [Foreign 2014; Delhi I, II, III 2013]
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Solution:
Ans. (i) Photodiode is fabricated with a transparent window to allow light to fall on the diode.
(ii) (a) Working : When a reverse biased photodiode is illuminated with the light of energy greater than the forbidden energy gap $\left(E_{g}\right)$, the electronhole pairs are generated in, or near, the depletion region. Due to junction field, electrons collected on the $n$-side and holes on $p$-side, giving rise to a potential difference.
(b)
[CBSE Marking Scheme 2013] 1
