Question

Impure semiconductor
1. has more conductivity in contrast to pure semiconductor
2. has less conductivity in contrast to pure semiconductor
3. has electrons and holes in equal number
4. has a fermi level which is in the centre of conduction and valence bands

Answer 1

Correct Answer - Option 1 : has more conductivity in contrast to pure semiconductor

CONCEPT:

• Intrinsic or Pure Semiconductor: The intrinsic semiconductor is a pure semiconductor.
  • Since they are pure semiconductors they have the same number of holes and electrons.
  • The conductivity of an intrinsic semiconductor is very low at room temperature.
• Extrinsic or Impure Semiconductor: We add a small amount of impurity to the pure semiconductor.
  • This increases the conductivity of the semiconductor by manifold.
  • This impure semiconductor is called an extrinsic semiconductor.

Therefore, the impure semiconductor has more conductivity in contrast to the pure semiconductor.