With the knowledge of the energy bands in semiconductors, the basic process explained in a light-emitting diode (LED) to light generation is used. With this device produced through appropriate structuring an area in which electrons from the conduction band of empty seats in the valence fall (also electron-hole recombination). This energy is released, with some probability, in the form of electromagnetic radiation is emitted.
Since the amount of energy given by the width of the forbidden energy sector narrowly defined, is the frequency of light (visible frequency range means that the color of light) sharply limited. An LED emits therefore principally with only one color.