10.1 : 半導体の基礎

Solids are composed of atoms with distinct electronic configurations and energy levels.

When two identical isolated atoms are brought close together, their interaction causes each energy level to split into two distinct levels.

This splitting is a result of the Pauli exclusion principle, which states that no two electrons in an atom can occupy the same energy state at the same time.

If several atoms are brought together to form a solid, the energy levels split to form a continuous band. At the equilibrium interatomic spacing, the band splits into the valence band and the conduction band.

At absolute zero temperature, the valence band comprises the energy levels filled with electrons.

Above the valence band lies the conduction band, which contains vacant energy levels.

The energy gap between these two bands is called the band gap. It represents the energy difference between the top of the valence band and the bottom of the conduction band.