Explain the two types of materials that are formed after doping.

Depending on the impurity added, extrinsic semiconductors can be then subdivided in two types of class:

N-type semiconductor

P- Type semiconductor

When to pure germanium, a small amount of pentavalent impurity that is antimony is added further. Four of the five valence electrons will involve covalent bonds, and fifth will be nominally unbound and that will be available as a carrier of current. Such are termed as N-type semiconductor. In such type of semiconductor electron are the majority carriers.

When a trivalent impurity as borson, and Gallilium are added to an intrinsic semiconductor, only three of the covalent bonds can be filled, and the vacancy which exists in the fourth bond constitutes a hole. That is termed as P type semiconductor wherein holes are the majority carriers.