Which one of the following elements on doping with germanium, make it a p-type semiconductor?
Which one of the following elements on doping with germanium, make it a p-type semiconductor?
$\mathrm{Bi}$
$\mathrm{Sb}$
As
Ga
Solution
The group 13 elements have 1 electron short to $\mathrm{Ge}$, thus giving rise to electron deficient bond or a hole which is responsible for electrical conductivity. Thus, group 13 elements (like Ga) on dopping with $\mathrm{Ge}$, make it $p$-type semiconductor. Here p-type specifies that conduction is through positive holes in them.