P type Materials
The P type material is obtained when a semiconductor is doped with a trivalent impurity such as Aluminium or Boron. P type material is a material which has holes as its majority carriers. Electrons are the minority Charge Carriers in P type materials. When a trivalent impurity is added to the crystal lattice of a semiconductor, there is a vacancy for every impurity atom added. This vacancy is called a hole.
N type Materials
N type materials are made when a semiconductor is doped with a pentavalent impurity. A pentavalent impurity is one whose atom has five electrons in its outermost orbit (valence electrons). Examples of pentavalent impurities are Phosphorous, Antimony, Bismuth. In an N type Material, electrons are the majority charge carriers while holes are the minority charge carriers.
When a semiconductor is doped with a pentavalent impurity for every impurity atom added, there is a free electron. These electrons are responsible for conduction.