(i) Ge is an element of 14th group (like Si) and has configuration 4s24p2. It has been doped with In, a 13th group element having 5s25p1 configuration i.e., element of 14th group has been doped with 13th group element. All three valence electrons of impurity atom (In) gets bonded with three out of four eectrons of Ge and one electron of Ge remains unbonded. Conductivity is due to unbonded electron of insulator, Ge. Therefore, it is a p-type semi-conductor.
(ii) Boron, B is an element of 13th group and has 2s22p1 configuration. It is doped with Si, an element of 14th group having 3s23p2 configuration. All three electrons of boron gets bonded with 3 out of 4 electrons of Si and 4th electron of impurity atom (i.e., Si) is responsible for conductivity. Thus it is a n-type semiconductor.