What are semiconductors? Give an example for n-type semiconductors.

Semiconductors are materials having electrical conductivity among that of insulators and conductors. This is because, in semiconductors, there is only a small difference in energy among the ?lled valence band of electrons and the empty conduction band. They are the solids which act as insulator at absolute zero but conduct electricity at ordinary temperatures. For instance, N-type semiconductor is obtained by doping Phosphorous or Arsenic on Silicon or Germanium