Formation of a p-n junctionp-n संधि का निर्माणFormation of a p-n junction

NCERT Fig 14.10 · Class 12 Physics · Chapter 14 · interactive diagram

Parts and what they mean

• p-region (p-क्षेत्र) — Holes are the majority carriers here.
• n-region (n-क्षेत्र) — Electrons are the majority carriers here.
• Metallurgical junction (धातुकर्मीय संधि) — The boundary inside one wafer where the p-region meets the n-region. It is made by adding a pentavalent impurity to part of a p-Si wafer, not by pressing two slabs together.
• Diffusion (विसरण) — Due to the concentration difference, holes diffuse p → n and electrons diffuse n → p. Both give a diffusion current from p to n.
• Drift (अपवाह) — The junction field pushes electrons from the p-side to the n-side and holes from the n-side to the p-side. The drift current is opposite to the diffusion current.
• Junction electric field (संधि विद्युत क्षेत्र) — Directed from the positive space charge (n-side) to the negative space charge (p-side). It grows as diffusion continues until drift balances diffusion.
• Depletion region (अवक्षय क्षेत्र) — The space-charge layers on both sides of the junction, emptied of free carriers. About 0.1 µm (one-tenth of a micrometre) thick.
• Fixed ions (स्थिर आयन) — Ionised acceptors (−) on the p-side and ionised donors (+) on the n-side. They are bonded in the lattice and cannot move.
• Holes (होल) — Majority carriers of the p-side.
• Free electrons (मुक्त इलेक्ट्रॉन) — Majority carriers of the n-side.

Original diagram drawn by Simple Learning Hub, based on NCERT Fig 14.10. Report a mistake