Physics - Semiconductors Question with Solution | TestHub
Statement-1 : When a P-N Junction is heavily doped, width of depletion region becomes very small.
Statement-2 : When a semiconductor is doped, the concentration of charge carriers increases.
Options:
Answer:
Solution:
Statement 2: doping adds donor or acceptor atoms, and each one supplies a free electron or hole, so the carrier concentration increases. It is true.
Statement 1: in the junction, these free carriers diffuse across and leave behind fixed ionized donor and acceptor atoms.
Heavier doping means a larger density of these fixed ionized dopants, so a larger space-charge density.
The junction potential barrier is then built across a much smaller width.
Here N is the dopant concentration; the relation assumes comparable barrier conditions.
So Statement 1 is true, and Statement 2 is true and is the correct explanation for it: doping raises the carrier and dopant-ion density, which narrows the depletion region. Answer A.
