Classify each of the following as either a p-type or a n -type semiconductor .
1. Ge doped with In 2 . Si doped with B .

Explanation

Both (1) and (2) come under "p-type semicondutors".
Reason : In both the cases dopants (i.e.) indian in case - (1) and Boron in case - (2) belong to III (or) `13^(th)` group . Si (or) Ge doped with III group element is known as p-type semi-conductor .
Explanation : Doping the silicon or germination element with III or `13^(th)` group element like "B", Al , Ga or In results in the substitution of some silicon atoms in its structure by the dopant .
The dopant has only three valency electrons . The fourth valency electron is required . It is left as a vacant place on the atom . It is known as an electron vacancy (or) a hole . The electron vacancy on an atom in the structure migrates from one atom to another . Hence it facilitates the electrical conductivity . Si (or) Ge , doped with elements that create a hole in the structure , is known as p-type semi- conductor .