When value of current increase in P-N junction, then the value of contact potential,

Options

A. decrease
B. increase
C. remain unchanged
D. depends on temperature

Answer

To solve the question regarding the relationship between the current in a P-N junction and the contact potential, we can break it down into several steps:

### Step-by-Step Solution:

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

**Hint**: Remember that the P-N junction is crucial for understanding how diodes operate.

2. **Contact Potential**:
- The contact potential (or built-in potential) is the voltage that exists across the junction due to the diffusion of charge carriers. It is established when the p-type and n-type materials are joined, creating an electric field that opposes further diffusion.

**Hint**: Contact potential is a result of charge carrier movement at the junction.

3. **Effect of Current Increase**:
- An increase in current in a P-N junction typically indicates an increase in the number of charge carriers. This can occur due to an increase in temperature, which causes more covalent bonds to break, leading to more free electrons and holes.

**Hint**: Think about how temperature affects the movement of charge carriers in semiconductors.

4. **Relationship Between Current and Contact Potential**:
- As the current increases (due to increased charge carriers), the contact potential decreases. This is because the increased number of charge carriers reduces the built-in electric field that opposes the flow of current.

**Hint**: Consider how the balance of charge carriers influences the electric field and potential across the junction.

5. **Conclusion**:
- Therefore, when the current in a P-N junction increases, the contact potential decreases.

**Hint**: Summarize the relationship: more current leads to fewer barriers (lower potential) for charge carriers.

### Final Answer:
When the value of current increases in a P-N junction, the value of contact potential decreases.