Question

Identify the incorrect statement :

• A. when a P-N junction diode is forward biased, the width of the depletion region decreases.
• B. when a P-N junction diode is reverse biased, the barrier potential increases
• C. a photon diode is operated in the reverse bias
• D. an LED is a lightly doped P-N junction diode which emits spontaneous radiation of forward biasing.

Answer 1

The Correct Option is D

• LEDs are heavily doped: They are designed with heavy doping to increase recombination efficiency and light emission.
• Correct description: LEDs emit spontaneous radiation under forward bias, but the doping is intentionally heavy, not light.

Why other options are correct:

• A: Forward bias reduces the depletion width by neutralizing the barrier potential.
• B: Reverse bias widens the depletion region and increases the barrier potential.
• C: Photodiodes operate in reverse bias to detect light by measuring leakage current.

Key Point: The error in D lies in the "lightly doped" claim, which contradicts standard LED design principles.