Question

Which of the following dopants is used in germanium to form n-type semiconductor ?

• A. B
• B. In
• C. Ga
• D. P

Hint:

n-type needs a group 15 dopant with five valence electrons.

Answer 1

The Correct Option is D

Step 1: Rule:
Doping with an element having more valence electrons than the host gives n-type, while fewer gives p-type.

Step 2: Apply:
Ge has 4. P has 5 (more), while B, In and Ga have 3 (fewer). So P is the n-type dopant (D).

Final Answer:
Phosphorus. \[ \boxed{\text{P}} \]