Question

Discuss the types of defects that may arise on doping LiF with MgF₂ and NiO with Li₂O.

Answer 1

When NiO is doped with Li2O, the mobile Li+ ions are easily entering into the NiO structure and occupies the Ni2+ sites, thus creating a impure crystal means it creat a defect to balance the charge and maintain the neutrality, thus for every Li+ on a Ni2+ site in the lattice results in the formation of a Ni3+ ion. These ion have a positive hole located on a Ni2+ cation which produces a high concentration of holes located in the nickel oxide and as it is creating electronic defects in crystal it called as valence induction and the material is a p-type semiconductor.