Explain doping.

(N/A) The process of increasing the conductivity of intrinsic semiconductors by adding a small amount of suitable impurities is known as $doping$. The added impurities are called $dopants$.
Doping is performed to modify the electronic properties of semiconductors like $Si$ or $Ge$. Depending on the nature of the impurity,two types of extrinsic semiconductors are formed:
$(i)$ $n$-type semiconductors: Formed by doping with electron-rich impurities (Group $15$ elements like $P$ or $As$ added to Group $14$ elements).
$(ii)$ $p$-type semiconductors: Formed by doping with electron-deficient impurities (Group $13$ elements like $B$ or $Al$ added to Group $14$ elements).