A `P`-type semiconductor can be obtained by adding

Options

A. arsenic to pure silicon
B. gallium to pure silicon
C. antimony to pure germanium
D. phosphorous to pure germanium

Answer

To determine how a `P`-type semiconductor can be obtained, we need to understand the process of doping and the types of elements involved.

### Step-by-Step Solution:

1. **Understanding P-Type Semiconductors**:
- A P-type semiconductor is formed when a semiconductor material (like silicon or germanium) is doped with certain elements that have fewer valence electrons than the semiconductor. This creates "holes" in the material, which can carry positive charge.

2. **Identifying the Doping Elements**:
- The elements used for doping to create P-type semiconductors are typically from Group 13 of the periodic table. These elements include boron, aluminum, gallium, indium, and thallium. They have three valence electrons.

3. **Analyzing the Options**:
- **Option 1**: Arsenic to pure silicon.
- Arsenic is a Group 15 element (5 valence electrons), so this option is incorrect for creating a P-type semiconductor.
- **Option 2**: Gallium to pure silicon.
- Gallium is a Group 13 element (3 valence electrons), making this option correct for creating a P-type semiconductor.
- **Option 3**: Antimony to pure germanium.
- Antimony is also a Group 15 element, so this option is incorrect.
- **Option 4**: Phosphorus to pure germanium.
- Phosphorus is another Group 15 element, making this option incorrect as well.

4. **Conclusion**:
- The only correct option for obtaining a P-type semiconductor is **Option 2: Gallium to pure silicon**.

### Final Answer:
A `P`-type semiconductor can be obtained by adding **gallium to pure silicon**.

---