Question

What change occurs when $\mathrm{AgCl}$ is doped with ${\mathrm{CdCl}}_2$?

Answer 1

Doping:

• “The conductivity of these intrinsic semiconductors is increased by adding an appropriate amount of suitable impurity. This process is called doping.”

Doping of $\mathrm{AgCl}$ with ${\mathrm{CdCl}}_2$:

• When $\mathrm{AgCl}$ is doped with ${\mathrm{CdCl}}_2$, a cationic vacancies are created which means silver ion displaces from its position in the lattice due to the presence of neighboring cadmium ions.
• When $\mathrm{AgCl}$ is doped with ${\mathrm{CdCl}}_2$, $2$ silver ions $\left({\mathrm{Ag}}^{+}\right)$ are displaced by $1$ cadmium ion $\left({\mathrm{Cd}}^{2+}\right)$. Thus, one cadmium ion occupies the position of one silver ion which makes up for the charge of two silver ions $\left({\mathrm{Ag}}^{+}\right)$. This type of vacancy is known as cationic vacancy.