Which one of the following is an example of donor impurity?

Options

A. Antimony
B. Indium
C. Silicon
D. Aluminium

Answer

To determine which of the given options is an example of a donor impurity, we need to understand what donor impurities are and their characteristics.

### Step-by-Step Solution:

1. **Define Donor Impurity**:
- Donor impurities are elements that have five valence electrons (pentavalent) and are used to dope semiconductors to create n-type materials. They provide extra electrons that can move freely and contribute to electrical conductivity.

2. **Identify Pentavalent Elements**:
- Common examples of donor impurities include:
- Phosphorus (P)
- Arsenic (As)
- Antimony (Sb)
- These elements have five valence electrons and can donate one electron to the conduction band of the semiconductor.

3. **Identify Trivalent Elements**:
- Trivalent impurities, which have three valence electrons, are used to create p-type semiconductors. Examples include:
- Aluminum (Al)
- Gallium (Ga)
- Indium (In)
- These elements accept electrons, creating holes in the semiconductor.

4. **Analyze the Given Options**:
- We need to look at the options provided (not specified in the question but inferred from the transcript):
- Antimony (Sb)
- Indium (In)
- Silicon (Si)
- Aluminum (Al)
- Among these, we can classify:
- Antimony (Sb) is a donor impurity (pentavalent).
- Indium (In) and Aluminum (Al) are trivalent and thus not donor impurities.
- Silicon (Si) is a tetravalent intrinsic semiconductor and also not a donor impurity.

5. **Conclusion**:
- The only example of a donor impurity from the options provided is **Antimony (Sb)**.

### Final Answer:
Antimony (Sb) is an example of donor impurity.