Give reason: (a)Why is Frenkel defect found in AgCl but not in NaCl? (b)What is the difference between Phosphorus doped and Gallium doped semiconductors ?

Give reason: (a)Why is Frenkel defect found in AgCl but not in NaCl?

1.	Give reason: (a)Why is Frenkel defect found in AgCl but not in NaCl? (b)What is the difference between Phosphorus doped and Gallium doped semiconductors ?
Answer» Solution :(a)Frenkel DEFECT is found in those ionic compounds in which differences in the SIZE of cation and anion is large. This is so in case of AgCl but not in case of NaCl. Due to SMALL size of silver cations `(Ag^+)` , they can fit into the interstitial sites but `Na^+` ions cannot fit into the interstitial sites (b)Silicon doped with PHOSPHORUS gives n-type whereas silicon doped with gallium FORMS p-type semiconductors.