Which one of the following statement is false?

Options

A. Pure Si doped with trivalent impurities gives a p - type semiconductor.
B. Majority carriers in a n - type semiconductor are holes.
C. Minority carriers in a p - type semiconductor are electrons.
D. The resistance of intrinisic semiconductor decreases with increases of temperature.

Answer

To solve the question, we need to analyze each statement provided and determine which one is false. Here’s the step-by-step breakdown:

### Step 1: Analyze the first statement
**Statement:** Pure silicon doped with trivalent impurities gives a p-type semiconductor.

**Explanation:**
- Pure silicon is an intrinsic semiconductor with a valency of 4.
- When trivalent impurities (which have a valency of 3) are added, they create "holes" (missing electrons) in the silicon structure.
- This process is known as p-type doping because the majority charge carriers become positive holes.

**Conclusion:** This statement is true.

### Step 2: Analyze the second statement
**Statement:** Majority carriers in n-type semiconductor are holes.

**Explanation:**
- In n-type semiconductors, pentavalent impurities (with a valency of 5) are added to silicon.
- This results in an excess of electrons, making electrons the majority carriers.
- Holes are present but in a minority compared to the electrons.

**Conclusion:** This statement is false.

### Step 3: Analyze the third statement
**Statement:** Minority carriers in p-type are electrons.

**Explanation:**
- In p-type semiconductors, holes are the majority carriers due to the trivalent doping.
- Electrons are indeed present but in smaller quantities, making them the minority carriers.

**Conclusion:** This statement is true.

### Step 4: Analyze the fourth statement
**Statement:** The resistance of an intrinsic semiconductor decreases with an increase in temperature.

**Explanation:**
- As temperature increases, more electrons gain enough energy to jump from the valence band to the conduction band.
- This increase in charge carriers (electrons) leads to higher conductivity and thus lower resistance.

**Conclusion:** This statement is true.

### Final Conclusion
After analyzing all the statements, we find that the second statement is false.

**Answer:** The false statement is: "Majority carriers in n-type semiconductor are holes."

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