Question

In an n-type semiconductor, electrons are majority charge carriers and holes are minority charge carriers. The charge of an n-type semiconductor is?

• A. \text{negative}
• B. \text{positive}
• C. \text{neutral}
• D. \text{depends on the dopant} \

Hint:

Although an n-type semiconductor has extra electrons, it remains neutral overall because the fixed positive charges of the donor atoms balance the free negative electrons.

Answer 1

The Correct Option is C

Step 1: Understanding n-Type Semiconductors
An n-type semiconductor is created by doping an intrinsic semiconductor (such as silicon) with a pentavalent impurity (such as phosphorus or arsenic). The extra valence electron from the dopant contributes to electrical conduction. Step 2: Charge of the Semiconductor
Although the majority charge carriers in an n-type semiconductor are electrons, the overall charge of the material remains neutral. This is because:
- The dopant atoms introduce free electrons, but they also become positively charged ions, maintaining overall charge neutrality.
- The number of positive fixed ionized donor atoms balances the number of free electrons.
Step 3: Why Other Options Are Incorrect
- Option (1) Negative: Incorrect because, despite having excess electrons as charge carriers, the overall semiconductor remains charge-neutral due to charge balance.
- Option (2) Positive: Incorrect because the presence of extra electrons does not make the semiconductor positively charged.
- Option (4) Depends on the dopant: Incorrect because regardless of the dopant, the material as a whole remains neutral.
Thus, the charge of an n-type semiconductor is neutral. \bigskip