What is a P-type and N-type semiconductor?

Hint: A semiconductor is a material which has an electrical conductivity in between the Pure conductors and Pure insulators. Semiconductors are basically those materials which have free electrons available for conduction but not in very high amounts and due to this they are good conductors which have less resistance and are preferred over conductors.

Complete answer:
Extrinsic semiconductors have impurities added to them which makes them more reliable for use as these impurities add more electrons in conduction bands. Semiconductors have lower resistance than a normal conductor.
P-Type Semiconductors
P-type semiconductors are formed when a trivalent impurity is added to them like aluminum, gallium etc. These impurities consist of group 3 elements and in this type of semiconductors holes act as majority charge carriers and electrons act as minority charge carriers. Holes are basically the void places created due to the movement of electrons. In this type of semiconductors holes density is significantly greater than the electron density.
N-Type Semiconductors
In N-Type semiconductors, pentavalent impurities are added to them like phosphorus etc. In this type of semiconductors impurities are added from group 4 elements. In N-type semiconductors, electrons are the majority charge carriers and holes are the minority charge carriers. In this type of semiconductors electron density is significantly greater than the holes density.

Note:
Basically, semiconductors are characterized in two parts, Intrinsic semiconductors and extrinsic semiconductors. Intrinsic semiconductors are pure semiconductors, they do not have any impurities added to them. While extrinsic semiconductors are further classified into two sub parts, these are N-Type and P-Type semiconductors.