Low-voltage blue electroluminescence in GaN

Blue electroluminescence has been obtained in GaN with the energy supplied to each electron lower than the energy of the emitted photons. This antistokes emission increased with the cube of the current. An external power efficiency of 3 × 10
^-4
was obtained. A tentative model of impact excitation by two hot electrons is proposed as the excitation mechanism. The prospects of practical applications of this phenomenon are discussed.