Notes

Semiconductor material is one whose electrical properties lies in between those of insulators and good conductors …

Semiconductor material is one whose electrical properties lies in between those of insulators and good conductors. In terms of energy bands, Semiconductor can be defined as those materials, which at room temperature have, partially filled conduction band, partially empty valance band and a small energy gap (of the order of 1 eV) between them.
Semiconductor
Image of Semiconductor