Question

In an impurity semiconductor, donor impurity atoms?

• A. Add holes to the valence band
• B. Remove electrons from the valence band
• C. Add electrons to the conduction band
• D. Add electrons to the valence band

Hint:

In semiconductors, donor atoms increase conductivity by providing extra electrons to the conduction band, which can move freely under an electric field.

Answer 1

The Correct Option is C

In an impurity semiconductor, donor impurity atoms introduce extra electrons into the material, which are typically provided by donor atoms that have more valence electrons than the host semiconductor. These donor electrons move into the conduction band, making the semiconductor more conductive. Therefore, the donor atoms add electrons to the conduction band.
- Add holes to the valence band: This option is incorrect because donor impurities donate electrons, not holes.
- Remove electrons from the valence band: This is incorrect as the process of introducing donor impurities does not remove electrons; it adds extra electrons to the conduction band.
- Add electrons to the conduction band: This is the correct option because donor atoms provide extra electrons that contribute to electrical conduction in the semiconductor.
- Add electrons to the valence band: This is incorrect, as donor electrons are not added to the valence band, but rather to the conduction band.
Thus, donor impurity atoms add electrons to the conduction band, increasing the material's conductivity.