Definition of conduction band
The conduction band is the energy space formed by free electrons. That is, the energy range of free-moving electrons in a solid structure. For metals, the energy band in which all valence electrons are located is the conduction band. For semiconductors, the energy band in which all valence electrons are located is the so-called valence band, and the energy band with higher energy in the parity band is the conduction band. At absolute zero temperature, the valence band of the semiconductor is full band (see energy band theory). After photoelectric injection or thermal excitation, some electrons in the valence band will cross the forbidden band/band gap and enter The empty band with higher energy, the electron in the empty band will become the conduction band-the conduction band.