This occurs when there are too many electrons in the conduction band of a semiconductor. These electrons drop spontaneously into vacant locations in the valence band, a photon being emitted for each electron. The emitted light is incoherent.
Decay of an excited atom to a ground or resting state by the random emission of one photon. The decay is determined by the lifetime of the excited state.
Radiation emitted when the internal energy of a quantum mechanical system drops from an excited level to a lower level without regard to the simultaneous presence of similar radiation. Examples of spontaneous emission include radiation from an LED and radiation from an injection laser below the lasing threshold.
In physics, spontaneous emission is the process by which an atom, molecule or nucleus in an excited state drops to a lower-energy state, resulting in the creation of a photon.