Concepts Of Physics MCQ Edition [Volume 2]PhysicsSemiconductors and Semiconductor Devices
When a p - n junction is reverse-biased, the current is nearly constant at 25 A . Upon being forward-biased at 200 mV , a current of 75 A is observed. Find the magnitude of the diffusion current when the diode is forward-biased at 200 mV .
Options
- A100 A
- B75 A
- C50 A
- D125 A
Correct answer
A. 100 A
Step-by-step solution
The net current in a p - n junction diode is the difference between the diffusion current and the drift current. I = I_ diffusion - I_ drift The drift current is due to minority charge carriers and is nearly independent of the applied bias voltage. It is equal to the reverse saturation current. I_ drift = 25 A When the diode is forward-biased, the net current is given as 75 A . 75 A = I_ diffusion - 25 A I_ diffusion = 75 A + 25 A = 100 A