Contact PotentialHardQuestion 20232
Question
Built-in potential (contact potential) in a p-n junction is approximately:
- A0 V
- B0.3 V for Ge, 0.7 V for SiCorrect
- C5 V
- D1.5 V
Correct answer
0.3 V for Ge, 0.7 V for Si
Explanation
The built-in potential V₀ arises from the ionised donor/acceptor charges in the depletion region. V₀ ≈ 0.3 V for Ge, ≈ 0.7 V for Si. This is the height of the potential barrier that majority carriers must overcome in forward bias.