Classify each of the following as being either a p-type or a n-type semiconductor

(i) Ge doped with In

Solution: ‘Ge’ belongs to group 14th in th periodic table and ‘In” belongs to the group 13th . thus, when ‘Ge’ is doped with ‘In’, it makes hole or electron vacancy and acts as p – type conductor.

(ii) Si doped with B.

Solution: ‘Si’ belongs to group 14th in the periodic table and ‘B’ belongs to group 13th. Thus, when ‘Si’ is doped with “B’, it makes hole or electron valance and acts as p – type conductor.