P-type semiconductors can only be explained against the backdrop of extrinsic semiconductors. An extrinsic semiconductor is one in which an impurity has been added to a pure semiconductor in order to enhance or alter its electrical properties. This process of the addition of impurities is called doping. A p-type semiconductor is one such extrinsic conductor.
|A p-type semiconductor is obtained by doping Silicon, which has four valence electrons (electrons in the outer orbit of atoms), with an element like Boron which has three valence electrons.
Chemicalbonds (in the form of covalent bonds) are formed between Boron and Silicon. Since boron offers only three electrons, the silicon atom is deficient of another electron to bond with. This vacancy is called a hole. The hole concentration in p-type semiconductors is what is responsible for increasing its conductivity.
It finds application in the manufacture of solar cells, which are composed of p-n junctions formed by p-type silicon and n-type silicon.