Animated Solution for Physics - Semiconductors: The impurity atoms with which pure silicon should be doped to make a $p$-type semiconductor are those of

Creating p-type Semiconductors

Start with pure silicon, a beautiful crystal where every atom shares its $4$ valence electrons perfectly with its neighbors. It's an excellent insulator at absolute zero. But in electronics, we want to control its conductivity.

Enter doping! By sprinkling in a tiny amount of impurity atoms, we can drastically change how silicon behaves.

To make a $p$-type semiconductor, we need positive charge carriers, which we call holes. We achieve this by introducing a trivalent impurity—an atom from Group $13$ of the periodic table, which has only $3$ valence electrons.

When a trivalent atom like Boron ($\text{B}$) or Aluminium ($\text{Al}$) takes the place of a Silicon atom in the crystal lattice, it tries to bond with its $4$ Silicon neighbors. But it only has $3$ electrons to share!

This leaves one bond incomplete, creating a vacancy. This vacancy is what we call a hole.

This hole acts as a positive charge carrier. It is ready to accept an electron from a neighboring bond. When an electron jumps into the hole, it leaves a new hole behind, effectively allowing the hole to move through the crystal and conduct current.

On the flip side, if we used pentavalent impurities like Phosphorus ($\text{P}$) or Antimony ($\text{Sb}$) from Group $15$, they would bring an extra $5^{\text{th}}$ electron, creating an $n$-type semiconductor.

So, to get our $p$-type material, Boron and Aluminium are the perfect candidates!