In the depletion region of an unbiased p-n junction diode there are

Options

A. Only electrons
B. Only fixed ions
C. Only holes
D. Both electrons and holes

Answer

To solve the question regarding the depletion region of an unbiased p-n junction diode, we will analyze the characteristics of the depletion region and the types of charge carriers present.

### Step-by-Step Solution:

1. **Understanding the p-n Junction**:
- A p-n junction is formed by joining p-type and n-type semiconductors. The p-type semiconductor has an abundance of holes (positive charge carriers), while the n-type semiconductor has an abundance of electrons (negative charge carriers).

2. **Formation of the Depletion Region**:
- When the p-n junction is formed, electrons from the n-type region diffuse into the p-type region and recombine with holes. Similarly, holes from the p-type region diffuse into the n-type region and recombine with electrons. This process leads to the formation of a depletion region where there are no free charge carriers (electrons or holes).

3. **Charge Carriers in the Depletion Region**:
- In the depletion region, the recombination of electrons and holes results in the presence of fixed ions. The p-type side will have fixed positive ions (due to the absence of holes), and the n-type side will have fixed negative ions (due to the absence of electrons).

4. **Conclusion**:
- Therefore, in the depletion region of an unbiased p-n junction diode, there are only fixed ions present. The free charge carriers (electrons and holes) are depleted in this region.

### Final Answer:
In the depletion region of an unbiased p-n junction diode, there are only fixed ions.

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