Under the electric field of a p-n junction, which carriers drift from the n-side to the p-side?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Holes
The positive space charge on the n-side and the negative space charge on the p-side set up a junction field. This field is directed from the n-side to the p-side. The motion of carriers under this field is called drift.
Option (1) Electrons — Incorrect. An electron is negative, so the field pushes it opposite to its direction. An electron on the p-side therefore drifts to the n-side. It does not drift from n to p.
Option (2) Holes — Correct. A hole behaves as a positive charge and moves along the field. So a hole on the n-side near the junction is swept across to the p-side.
Option (3) Majority carriers — Incorrect. The majority carriers of the n-side are electrons. The junction field opposes their crossing to the p-side. The holes that drift from the n-side are its minority carriers.
Option (4) Ions — Incorrect. The ionised donors and acceptors are bonded to the surrounding atoms of the crystal and are immobile, so they cannot drift.
NCERT (2026-27):
p-n Junction Formation – “… Due to the positive space-charge region on n-side of the junction and negative space charge region on p-side of the junction, an electric field directed from positive charge towards negative charge develops. Due to this field, an electron on p-side of the junction moves to n-side and a hole on n-side of the junction moves to p-side. The motion of charge carriers due to the electric field is called drift.”