In unbiased p-n junction diode

In an unbiased p-n junction, the diffusion of charge carriers creates a depletion region containing immobile ions: negatively charged acceptors on the p-side and positively charged donors on the n-side.

An electric field arises from these immobile charges, directed from the positive ions (n-side) to the negative ions (p-side). Consequently, the n-type side is at a higher potential than the p-type side.

Option A is false due to the established potential barrier. Option B incorrectly reverses the electric field direction. Option C correctly identifies the field direction from n-type to p-type. Option D is incorrect as the n-type side has higher potential.