Majority and minority charge carriers

Charge carriers in semiconductor materials are either electrons, which have a unit negative charge, or holes, having a unit positive charge. In any semiconductor material, some of the current is in the form of electrons passed from atom to atom in a negative- to-positive direction. Some current occurs as holes that move from atom to atom in a positive-to-negative direction.
Sometimes electrons dominate the current flow in a semiconductor; this is the case if the material has donor impurities. In substances having acceptor impurities, holes dominate. The dominating charge carriers (either electrons or holes) are the majority carriers. The less abundant ones are the minority carriers.
The ratio of majority to minority carriers can vary, depending on the nature of the semiconducting material.