n -Type of Semiconductor

 Explain n-type semiconductor with an example.

(i) n-type semiconductor is an extrinsic semiconductor obtained by doping an intrinsic semiconductor with increased number of electron in the conduction band.

(ii) Doping of Silicon with Phosphorus Silicon is a crystal structure in which each Si atom is tetrahedrally linked to four other Si atoms.

(iii) When a small quantity of P is added to pure Si, the P atoms occupy some vacant sites in the lattice in place of Si atoms.

(iv) Four of the five valence electrons of P are utilized in bonding the closest of the four Si atoms, thus P has one extra electron than needed for bonding.

(vi) Therefore, the number of electrons in the conduction band of the doped Si are more than those in the conduction band of pure Si. This increases the conductivity of the doped Silicon.

 examples of n-type semiconductor.

Ans. Si or Ge doped with group 15 elements such as P,As,Sb or Bi are examples of n- type of semiconductor.