When Si is doped with ________ an n-type semiconductor is formed.

Concept:

• An n-type semiconductor is an extrinsic semiconductor doped with phosphorus (P), arsenic (As), or antimony (Sb) as an impurity.
• Silicon of Group IV has four valence electrons and phosphorus of Group V has five valence electrons.
• If a small amount of phosphorus is added to a pure silicon crystal, one of the valence electrons of phosphorus becomes free to move around as a surplus electron.
• When this free electron is attracted to the “+” electrode and moves, current flows.

Explanation:

• When Si is doped with Phosphorus an n-type semiconductor is formed.
• When Si is doped with Boron, indium an p-type semiconductor is formed.

Additional Information

•  A p-type semiconductor is an extrinsic semiconductor doped with boron (B) or indium (In). .
• Silicon of Group IV has four valence electrons and boron of Group III has three valence electrons.
• If a small amount of boron is doped to a single crystal of silicon, valence electrons will be insufficient at one position to bond silicon and boron, resulting in holes that lack electrons.
• When a voltage is applied in this state, the neighboring electrons move to the hole, so that the place where an electron was present becomes a new hole, and the holes appear to move to the "–" electrode in sequence.
•