Concepts Of Physics MCQ Edition [Volume 2]PhysicsSemiconductors and Semiconductor Devices
A potential barrier of 250 meV exists across a p - n junction. A hole possessing a kinetic energy of 300 meV approaches the junction from the p -side. Determine the kinetic energy of the hole after it crosses the junction.
Options
- A550 meV
- B300 meV
- C250 meV
- D50 meV
Correct answer
D. 50 meV
Step-by-step solution
The potential barrier across a p - n junction opposes the motion of majority charge carriers. The electric field in the depletion region is directed from the n -side to the p -side. When a hole (which acts as a positive charge) moves from the p -side to the n -side, it moves against the electric field and loses kinetic energy equal to the potential barrier energy. By conservation of energy, the final kinetic energy K_ f of the hole after crossing the junction is given by: K_ f = K_ i - e V₀ where K_ i is the initia