Question

What do you understand by doping of a crystal?

Answer 1

1. Doping a crystal refers to the process of adding a small amount of impurity to a pure crystalline substance, usually a semiconductor, to change or enhance its electrical conductivity.
2. The impurity-doped silicon and germanium act as semiconductors. Their conductivity increases with an increase in temperature.
3. Group 14 (Group IVA) elements doped with group 15 (Group VA) elements conduct electricity through normal electron conduction mechanisms and are known as n-type semiconductors. The process involves the use of a pentavalent element, such as phosphorus.
4. On the other hand, the group 14 elements doped with group 13 (IIIA) elements conduct electric current through electron-deficient bonds or holes and are called p-type semiconductors. The process involves the use of a trivalent element, such as boron.