Developments for enhancing the luminous intensity of LEDs by optimizing their structures

Abstract The brightness enhancement of the light emitting diode (LED) can satisfy the increasing demands of illumination of human beings. However, the low-rate recombination of electron-hole pairs, isotropic nature of the spontaneous emission as well as the large refractive index of the materials used for LEDs usually limits the performance of the light output. Therefore, it is necessary to address these challenges, trying to enlarge the light output power with high optoelectronic efficiency. This review will analysis the factors that can influence the behaviour of the LEDs and the method to overcome these issues by optimizing the structures of epilayers and LED chips.