Concepts Of Physics MCQ Edition [Volume 2]PhysicsSemiconductors and Semiconductor Devices
The drift current in a p - n junction is given to be 20.0 A . Estimate the number of electrons crossing a cross section per second within the depletion region.
Options
- A2.50 10¹⁴
- B3.12 10¹³
- C6.25 10¹³
- D1.25 10¹⁴
Correct answer
C. 6.25 10¹³
Step-by-step solution
The drift current in a p - n junction is due to the flow of minority charge carriers across the depletion region, which includes both electrons and holes. Total drift current, I = 20.0 A . To estimate the number of electrons, we assume that electrons and holes contribute equally to the drift current. Thus, the current due to electrons is: I_e = I 2 = 10.0 A = 10.0 10⁻⁶ A The number of electrons crossing the cross-section per second is: n = I_e e n = 10.0 10⁻⁶ 1.6 10⁻¹⁹ n = 6.25 10¹³