Intrinsic semiconductors are semiconductors which do not contain impurities. They do contain electrons as well as holes. The electron density equals the hole density since the thermal activation of an electron from the valence band to the conduction band yields a free electron in the conduction band as well as a free hole in the valence band.
The most common examples of the intrinsic semiconductors are silicon and germanium. Both these semi conductors are used frequently in manufacturing of transistors and electronic products manufacturing. The electronic configuration of both these semiconductors is shown below:
Germanium -1s22s22p63s23p6 3d104s24p2
Silicon: 1s2 2s2 2p6 3s2 3p2
intrinsic semi conductor:
a pure semi conductor having no impurity added and that conducts electric current only by thermal aggitation and has no free electons/holes by itself.
e.g.silicon and germenium in their pure state are termed as intrinsic semi conductors.