CBSE Class 12 · 1998 · SemiconductorsShort Answer

Define the terms 'potential barrier' and 'depletion region' for a p-n junction diode.

Solution

During junction formation, diffusion leaves immobile negative ions on the p-side and positive ions on the n-side.
The resulting potential difference across the junction, which opposes further diffusion of majority carriers, is the potential barrier (~0.3 V for Ge, ~0.7 V for Si).
The thin carrier-free layer containing only these immobile ions is the depletion region (~

1 μ m

wide).

Barrier opposes diffusion; depletion layer is carrier-free.

CBSE Class 12 Board · 1998 · Subjective

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