In an n-type semiconductor, the electrons are the majority carriers whereas, the holes are the minority carriers. In the p-type semiconductor material, the holes are the majority carriers, whereas, the electrons are the minority carriers as shown in the figures below:
When a small amount of Pentavalent impurity is added to a pure semiconductor, it provides a large number of free electrons in the crystal forming the n-type semiconductor. Some of the covalent bonds break even at the room temperature, releasing a small number of electron-hole pairs.
Thus, an n-type semiconductor contains a large number of free electrons and a few numbers of holes. This means the electron provided by pentavalent impurity added and a share of electron-hole pairs. Therefore, in n-type semiconductor, most of the current conduction is due to the free electrons available in the semiconductor.
Similarly, in the p-type semiconductor, the holes are in the majority as compared to electrons, and the conduction takes place because of the very few electrons which are present in the minority.
Also See: n-Type Semiconductor
Also See: p-Type Semiconductor