Match List-I with List-II for the energy band diagrams of doped silicon.
| List-I | List-II |
|---|---|
| (A) Donor level \(E_D\) in n-type Si | (I) \(E_C-E_V\) |
| (B) Acceptor level \(E_A\) in p-type Si | (II) Slightly above the top of the valence band |
| (C) Energy gap \(E_g\) | (III) Slightly below the bottom of the conduction band |
| (D) Ionisation energy of a donor atom in n-type Si | (IV) \(E_C-E_D\) |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A)-(III), (B)-(II), (C)-(I), (D)-(IV)
(A) Donor level \( E_D \) in n-type Si — This matches (III). The donor level lies in the gap, just under the conduction band.
(B) Acceptor level \( E_A \) in p-type Si — This matches (II). The acceptor level lies in the gap, just above the valence band. An electron from the valence band can reach it with a very small energy.
(C) Energy gap \( E_g \) — This matches (I). The gap runs from the top of the valence band, \( E_V \), to the bottom of the conduction band, \( E_C \).
(D) Ionisation energy of a donor atom in n-type Si — This matches (IV). It is the energy needed to set the extra electron of the donor free. The electron rises from \( E_D \) to \( E_C \), a very small step.
NCERT (2026-27):
Extrinsic Semiconductor – “… In the energy band diagram of n-type Si semiconductor, the donor energy level ED is slightly below the bottom EC of the conduction band and electrons from this level move into the conduction band with very small supply of energy. …”
Extrinsic Semiconductor – “… Similarly, for p-type semiconductor, the acceptor energy level EA is slightly above the top EV of the valence band …”
Classification of Metals, Conductors and Semiconductors – “The gap between the top of the valence band and bottom of the conduction band is called the energy band gap (Energy gap Eg). …”