Band gap introduction

Band gap introduction

Band gap (Band gap) refers to a band gap width (unit is electron volts (ev)), the energy of electrons in a solid can not be continuous value, but some discontinuous energy bands, it is necessary to conduct electricity Free electrons or holes exist. The energy band where free electrons exist is called the conduction band (which can conduct electricity), and the energy band where free holes exist is called the valence band (which can also conduct electricity). For the bound electron to become a free electron or hole, it must obtain enough energy to transition from the valence band to the conduction band. The minimum value of this energy is the forbidden band width.