Question

Why are doped better than pure semi conductor?

Answer 1

Semiconductors can conduct electricity in molten state while in solid state they act as insulators. But on adding impurity or doping, the semi-conductors become either n-type (means having an extra electron in an interstitial site) and the electricity is conducted due to the presence of free electron or it it can be p-type semiconductor which conducts electricity due to the absence of an electron or presence positive hole. So doped semiconductors can conduct electricity far better than the semiconductors without doping.