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 need to understand the concept of doping and the types of semiconductors.

### Step-by-Step Solution:

1. **Identify the Group of Germanium**:
Germanium (Ge) is a group 14 element. Elements in this group have four valence electrons.

2. **Understand Doping**:
Doping is the process of adding impurities to a semiconductor to change its electrical properties. There are two types of doping:
- **n-type doping**: Involves adding elements from group 15 (which have five valence electrons) to create extra electrons (negative charge carriers).
- **p-type doping**: Involves adding elements from group 13 (which have three valence electrons) to create "holes" (positive charge carriers).

3. **Determine the Type of Semiconductor**:
To convert germanium into a p-type semiconductor, we need to add an element from group 13. This is because group 13 elements have one less electron than germanium, which leads to the formation of holes.

4. **Select a Suitable Dopant**:
Common group 13 elements that can be used for doping include:
- Boron (B)
- Aluminum (Al)
- Gallium (Ga)
- Indium (In)

5. **Conclusion**:
Any of the group 13 elements, when doped into germanium, will convert it into a p-type semiconductor. For example, if we choose Indium (In), it has three valence electrons and will create holes in the germanium crystal structure.

### Final Answer:
When doped into a crystal of ultrapurified germanium, elements from group 13, such as Indium (In), will convert it into a p-type semiconductor.

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