In a p- n junction diode not connected to any circuit,

Options

A. Potential is the same every where
B. The P-type side is at a higher potential than the N-type side
C. There is an electric field at the junction directed from the N-type side to the P-type side
D. There is an electric field at the junction directed from the P-type side to the N-type side

Explanation

To solve the question regarding the behavior of a p-n junction diode not connected to any circuit, we can break it down into the following steps:

### Step-by-Step Solution:

1. **Understanding the Structure of a p-n Junction Diode**:
- A p-n junction diode consists of two types of semiconductor materials: p-type and n-type. 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 a p-n junction is formed, electrons from the n-type region will diffuse into the p-type region and recombine with holes. Similarly, holes from the p-type region will diffuse into the n-type region and recombine with electrons.
- This movement of charge carriers leads to the formation of a depletion region at the junction, where there are no free charge carriers (electrons or holes).

3. **Electric Field Creation**:
- As electrons leave the n-type region and recombine with holes in the p-type region, the n-type side becomes positively charged (due to the ionized donor atoms), and the p-type side becomes negatively charged (due to the ionized acceptor atoms).
- This separation of charge creates an electric field in the depletion region.

4. **Direction of the Electric Field**:
- The electric field in the depletion region is directed from the n-type region to the p-type region. This is because the positive charge (from the n-type) is on the side of the n-type material and the negative charge (from the p-type) is on the side of the p-type material.

5. **Conclusion**:
- Therefore, in a p-n junction diode that is not connected to any circuit, an electric field is established in the depletion region, directed from the n-side to the p-side.

### Final Answer:
- The electric field in the depletion region of a p-n junction diode not connected to any circuit is directed from the n-type side to the p-type side.