Question

In an intrinsic semiconductor, the Fermi energy level is

• A. nearer to valence band than conduction band.
• B. equidistant from conduction band and valence band.
• C. nearer to conduction band than valence band.
• D. bisecting the conduction band.

Answer 1

Answer: (B)

equidistant from conduction band and valence band.

Fermi energy is determined as the energy point where the probability of occupancy by an electron is exactly $50$ or $0.5$, i.e., $\frac{1}{2}$. For the intrinsic semiconductor, since electrons and holes are always created in pairs, $n=p=ni$. Hence, there are equal number of holes and electrons in valence band and conduction band respectively. Therefore, the Fermi energy level is equidistant from conduction band and valence band.