NEETPhysicsSemiconductors
Identify the incorrect statement regarding special purpose p-n junction diodes:
Options
- AA Zener diode is heavily doped, resulting in a very thin depletion region and a high electric field at the jun
- BA Light Emitting Diode (LED) is a heavily doped p-n junction which under forward bias emits spontaneous radiat
- CIn a photodiode, the reverse saturation current is independent of the intensity of incident light.
- DA solar cell operates without any external bias and generates an emf when light falls on it.
Correct answer
C. In a photodiode, the reverse saturation current is independent of the intensity of incident light.
Step-by-step solution
A photodiode is operated in reverse bias. When it is illuminated with light of energy greater than the bandgap of the semiconductor, electron-hole pairs are generated. The magnitude of the photocurrent (reverse saturation current) is directly proportional to the intensity of incident light. Therefore, the statement claiming it is independent of light intensity is incorrect. Zener diodes and LEDs are heavily doped p-n junctions. Heavy doping in a Zener diode leads to a thin depletion region and a high electric field