Question

Which of the following statements is NOT TRUE?

• A. The majority carriers in n-type semiconductors are electrons.
• B. The resistance of an intrinsic semiconductor decreases with increase in temperature.
• C. Doping pure silicon crystal with trivalent impurities gives p-type semiconductor.
• D. The majority carriers in n-type semiconductors are holes.

Hint:

In an n-type semiconductor the donor atoms supply electrons, so electrons are the majority carriers.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
Doping with a pentavalent impurity gives an n-type semiconductor with free electrons. Doping with a trivalent impurity gives a p-type semiconductor with holes.

Step 2: Check each statement
(A) True: electrons are the majority carriers in n-type.
(B) True: heating creates more electron-hole pairs, so the resistance of an intrinsic semiconductor falls.
(C) True: trivalent doping gives p-type.

Step 3: Find the false one
(D) says holes are the majority carriers in n-type, which is wrong. Holes are the minority carriers there.

Final Answer:
Statement (D) is not true. \[ \boxed{\text{(D) }\text{The majority carriers in n-type semiconductors are holes.}} \]