Which of the following , when doped into a crystal of ultrapurified germanium , will convert it into a p - type semiconductor ?

Options

A. C
B. As
C. In
D. Na

Answer

To determine which element, when doped into a crystal of ultrapurified germanium, will convert it into a p-type semiconductor, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Semiconductor Doping**:
- Semiconductors can be modified by adding impurities, a process known as doping. There are two types of doping: n-type and p-type.
- N-type doping involves adding elements from group 15 of the periodic table, which have more valence electrons than the semiconductor (like phosphorus in silicon).
- P-type doping involves adding elements from group 13, which have fewer valence electrons than the semiconductor (like boron in silicon).

2. **Identifying the Semiconductor**:
- The question specifies that we are working with ultrapurified germanium (Ge). Germanium has four valence electrons.

3. **Choosing the Doping Element**:
- To convert germanium into a p-type semiconductor, we need to add an element from group 13 (which has three valence electrons). This will create "holes" in the semiconductor structure, allowing it to conduct electricity through the movement of these holes.

4. **Analyzing the Options**:
- Among the options provided (let's assume they are A, B, C, D), we need to identify which one is from group 13.
- The element indium (In), with atomic number 49, is from group 13.

5. **Conclusion**:
- Since indium is the only element listed that belongs to group 13, doping germanium with indium will convert it into a p-type semiconductor.

### Final Answer:
- The correct answer is **option C: Indium (In)**.