Druing P-N junction formation when the electron and holes stops moving from P to N and N to P, then

Options

A. there is increase in number of `+ve` and `-ve` ions at junction
B. there is increase in number of electrons at junction.
C. there is increase in number of holes at junction
D. there is increase in number of holes and electrons at junctions

Answer

To solve the question regarding what happens during the formation of a P-N junction when electrons and holes stop moving from P to N and N to P, we can break it down into a series of steps:

### Step-by-Step Solution:

1. **Understanding P-N Junction Formation**:
- A P-N junction is formed by bringing together 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. **Movement of Charge Carriers**:
- When the P-N junction is formed, electrons from the N-side start to diffuse into the P-side where there are holes. Similarly, holes from the P-side diffuse into the N-side where there are electrons.

3. **Establishment of Equilibrium**:
- As electrons move from the N-side to the P-side and holes move from the P-side to the N-side, they recombine at the junction, leading to a depletion region where there are no free charge carriers.

4. **Formation of Ionized Atoms**:
- As the electrons and holes recombine, the P-side becomes positively charged due to the unneutralized acceptor ions, while the N-side becomes negatively charged due to the unneutralized donor ions. This creates an electric field at the junction.

5. **Stopping of Carrier Movement**:
- Eventually, the electric field created by the ionized atoms opposes further movement of electrons and holes. This results in a state where the diffusion of charge carriers stops, and the system reaches equilibrium.

6. **Conclusion**:
- Therefore, when the electrons and holes stop moving from P to N and N to P, it indicates that the depletion region has formed, and the junction is now stable with an electric field preventing further diffusion of charge carriers.

### Final Answer:
When the electrons and holes stop moving from P to N and N to P during P-N junction formation, it results in the establishment of a depletion region with positive and negative ionized atoms at the junction, leading to equilibrium.