Question

When boron is mixed as impurity in silicon, then resultant matter is

• A. n-type semiconductor
• B. p-type semiconductor
• C. n-type conductor
• D. p-type conductor

Hint:

In p-type semiconductors, the impurity atom (like boron) creates "holes" that serve as the majority charge carriers.

Answer 1

The Correct Option is B

Step 1: Type of semiconductor.
When boron, a trivalent element, is added as an impurity to silicon, it creates a "hole" or absence of an electron in the silicon lattice. These "holes" are positive charge carriers, leading to the formation of a p-type semiconductor.
Step 2: Explanation of p-type semiconductor.
In p-type semiconductors, the majority charge carriers are holes, which are created by the absence of electrons. As a result, the electrical conductivity is facilitated by the movement of holes.
Step 3: Elimination.
- (A) n-type semiconductor: Incorrect, n-type semiconductors are formed by adding pentavalent impurities (e.g., phosphorus).
- (B) p-type semiconductor: Correct, as boron creates "holes" that act as majority charge carriers.
- (C) n-type conductor: Incorrect, this refers to a conductor with excess electrons.
- (D) p-type conductor: Incorrect, semiconductors are being discussed, not general conductors.
Step 4: Conclusion.
Thus, when boron is added as an impurity in silicon, it forms a p-type semiconductor.