ABSTRACT
In the last chapter we discussed some basics of semiconductors in general. The best known and technically still most important semiconductor is silicon (Si). Like germanium (Ge), it is an elemental semiconductor. Both have a band gap around 1eV (see Table 2.1). These elements are positioned in the center of the periodic system of elements (PSE). They have four valence electrons forming four covalent bonds in tetragonal symmetry resulting in a diamond-like crystal structure (fcc) . Indeed, diamond is another representative of this class of semiconductors, having a fairly large band gap of E g ≃ 5.5eV These materials have an indirect band structure.
