ABSTRACT
The two most technologically important elemental semiconductors belonging to group IV of the periodic table are silicon and germanium. Both have the diamond type of crystal structure characterized by high stability. The fundamental optical transition in these semiconductors is indirect with a band-gap energy of ~1.1 eV for silicon and 0.67 eV for germanium. Both silicon and germanium can be doped with group III or V elements to give p- or n-type materials.
