Explanation:

Reverse-biased p-n junction is a semiconductor device that operates on the principle of rectification. When a p-n junction is reverse-biased, the positive terminal of the battery is connected to the n-type semiconductor and the negative terminal to the p-type semiconductor. This creates a depletion region in the middle of the junction.

Electric field

The depletion layer of the p-n junction contains a potential difference due to the opposing charges on each side of the junction. This potential difference creates an electric field that opposes the flow of current through the junction. In a reverse-biased p-n junction, the electric field is directed from the p-type semiconductor to the n-type semiconductor.

Electric field in the middle of the depletion layer

In the middle of the depletion layer, the electric field is zero. This is because the electric field is caused by the potential difference between the p-type and n-type semiconductors. In the middle of the depletion layer, the potential is constant, so there is no potential difference and hence no electric field.

Potential

The potential in the middle of the depletion layer is the maximum potential difference across the p-n junction. This potential difference is known as the reverse breakdown voltage and is the maximum voltage that can be applied across the p-n junction without causing breakdown.

Conclusion

In conclusion, in the middle of the depletion layer of a reverse-biased p-n junction, the electric field is zero and the potential is maximum. This is because the potential difference across the junction is maximum at this point, but there is no electric field due to the constant potential in the middle of the depletion layer.