Concept:When electrons diffuse from the n-region into the p-region, they leave behind positively charged, immobile donor ion cores (such as \(\text{P}^+\) or \(\text{As}^+\)) in the n-side of the depletion region.
Formula:Qualitative concept / No formula required.
Solution:- N-side dopants are pentavalent donor atoms that become fixed positive ions (\(\text{Donor}^+\)) after losing an electron.
- P-side dopants are trivalent acceptor atoms that become fixed negative ions (\(\text{Acceptor}^-\)) after gaining an electron.
- Thus, positive space charge resides on the n-side of the depletion region, and negative space charge resides on the p-side.
Why other options are incorrect:- Option A: The p-side of the depletion region contains fixed negative acceptor ions.
- Option B: The neutral bulk p-region has equal numbers of mobile holes and fixed negative ions, giving zero net space charge.
- Option D: The neutral bulk n-region has zero net space charge.
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