(a) How is a photodiode fabricated ?
(b) Briefly explain its working. Draw its V-I characteristics for two different intensities of illumination.
a) Photodiode is fabricated with a transparent window to allow light to fall on the diode.
(b) (i) Working : When a reverse biased photodiode is illuminated with the light of energy greater than the forbidden energy gap (E.,), the electron- hole pairs are generated in, or near, the depletion region. Due to junction field, electrons are collected on the n-side and holes on p-side, giving rise to a potential difference.
