ABSTRACT
In this chapter we introduce concepts related to semiconductors and semiconductor devices. The primary aim of this chapter is to introduce the unfamiliar reader to semiconductor device analysis.
The electrons of a single isolated atom of any element occupy atomic orbitals that are assigned certain discrete energy levels. The energy levels are quantized and there are certain energies that the electrons can never possess called the forbidden energy levels. If several atoms are brought together into a molecule, their atomic orbitals split. As more and more atoms are brought together, a large number of orbitals are created with the separation in their energy levels becoming smaller. Solids, which are composed of a large number of atoms (about 1023), thus have a large number of orbitals occupying a large number of finely separated energy levels called energy bands. The forbidden energy levels form energy band gaps between bands.
