Practice portal › Semiconductor Electronics › p-n Junction Formation
Asked in CBSE AIPMT 2002 · Depletion region and barrier potential
Idea: when the junction forms, electrons diffuse from n to p and holes from p to n.
Each electron leaving the n side exposes a positive donor ion that cannot move; each hole leaving the p side exposes a negative acceptor ion.
So the n side of the junction is left with fixed positive charge and the p side with fixed negative charge.
That puts the n side at the higher potential, and the resulting field is what stops further diffusion.
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