p-type semiconductors are formed when Si or Ge are doped with:

Options

A. Group 14 elements
B. Group 15 elements
C. Group 13 elements
D. Group 18 elements

Explanation

To solve the question regarding the formation of p-type semiconductors when silicon (Si) or germanium (Ge) are doped, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Semiconductors**:
- Semiconductors are materials that have electrical conductivity between that of conductors and insulators. Silicon and germanium are two common semiconductors.

2. **Valence Electrons**:
- Silicon and germanium belong to Group 14 of the periodic table, which means they have 4 valence electrons.

3. **Doping Process**:
- Doping is the process of adding impurities to a semiconductor to change its electrical properties.

4. **Types of Doping**:
- There are two types of doping: n-type and p-type.
- In n-type doping, elements with more valence electrons (like Group 15 elements) are added, which provide extra electrons.
- In p-type doping, elements with fewer valence electrons (like Group 13 elements) are added, which create "holes" or vacancies where an electron is missing.

5. **Group 13 Elements**:
- Group 13 elements, such as boron (B), aluminum (Al), and gallium (Ga), have 3 valence electrons.

6. **Formation of Holes**:
- When a Group 13 element is doped into silicon or germanium, it will bond with the surrounding silicon or germanium atoms. However, since it has only 3 valence electrons, it cannot form a complete bond with 4 neighboring silicon or germanium atoms.
- This results in an electron hole, which is a vacancy where an electron is missing.

7. **Conclusion**:
- Therefore, when silicon or germanium is doped with Group 13 elements, p-type semiconductors are formed due to the creation of holes, which enhance the conductivity of the material.

### Final Answer:
P-type semiconductors are formed when silicon (Si) or germanium (Ge) are doped with Group 13 elements such as boron (B), aluminum (Al), or gallium (Ga).