Doping of a Semiconductor

Semiconductor(अर्धचालक)|Doping Of Semiconductor(सेमीकंडक्टर का डोपिंग)|Questions(प्रश्न )|Summary

What is meant by 'doping' in a semiconductor ?

After doping, resistivity of a semiconductor

When a p-type impurity is doped in a semiconductor,a large number of holes are created. This does not make the semiconductor chared.But when holes diffuse from the p-side to the n-side in a p-n junction,the n-side gets positvely charged.Explain.

When an impurity is doped into an intrinsuc semiconductor,the conductivity of the semiconductor

When on impurity is doped into an intrinsic semiconductor, the conductivity of the semiconductor

A pure semiconductor germanium or silicon, free of every impurity is called intrinsic semiconductor. A room temperature, a pure semiconductor has a very small number of current carriers (electrons and holes). Hence, its conductivity is low. When the impurity atoms of valence five or three are doped in a pure semiconductor, we get repectively n-type ot p-type extrinsic semiconductor. In case of a doped semiconductor. n_(e)n_(h)=n_(i)^(2) , where n_(e) and n_(h) are the number density of electrons and holes respectively and n_(i) is the number density of intrinsic charge carriers in a pure semiconductor. The conductivity of extrinsic semiconductor is much higher than that of intrinsic semiconductor. (i) Name two materials to be doped in pure semiconductor of silicon to get p-type semiconductor n-type semiconductor. (ii) What do you learn from the above study?