Which of the following energy band diagrams shows the `N`-type semiconductor?

Options

A.
B.
C.
D.

Explanation

To determine which energy band diagram represents an N-type semiconductor, we need to understand the characteristics of N-type semiconductors.

### Step-by-Step Solution:

1. **Understanding N-type Semiconductors**:
- N-type semiconductors are created by doping a pure semiconductor (like silicon) with a pentavalent atom (e.g., phosphorus).
- The pentavalent atoms contribute extra electrons, which become the majority charge carriers.

2. **Energy Band Diagram Characteristics**:
- In the energy band diagram of an N-type semiconductor, the conduction band (CB) must be positioned higher than the valence band (VB).
- There should be an impurity energy level (donor level) that is very close to the conduction band. This is because the extra electrons from the dopant easily move into the conduction band.

3. **Identifying the Correct Diagram**:
- Look for a diagram where:
- The conduction band is higher than the valence band.
- The impurity level (donor level) is positioned just below the conduction band, indicating that electrons can easily be excited into the conduction band.

4. **Analyzing the Options**:
- Review the provided energy band diagrams and identify the one that meets the criteria mentioned above.
- The correct diagram will show the conduction band at a higher energy level with a donor level very close to it.

5. **Conclusion**:
- After analyzing the options, the diagram that shows the conduction band with an impurity level just below it is the representation of an N-type semiconductor.

### Final Answer:
- The correct energy band diagram that shows the N-type semiconductor is **Option 2**.