Enhanced light-extraction in GaInN near-ultraviolet light-emitting diode with Al-based omnidirectional reflector having NiZn∕Ag microcontacts

Enhancement of light extraction in a GaInN near-ultraviolet light-emitting diode (LED) employing an Al-based omnidirectional reflector (ODR) consisting of GaN, a SiO2 low-refractive-index layer perforated by an array of NiZn∕Ag microcontacts, and an Al layer is presented. A theoretical calculation reveals that a SiO2∕Al ODR has much higher reflectivity than both a SiO2∕Ag ODR and a Ag reflector at a wavelength of 400nm. It is experimentally shown that GaInN near-ultraviolet LEDs with GaN∕SiO2∕Al ODR have 16% and 38% higher light output than LEDs with SiO2∕Ag ODR and Ag reflector, respectively. The higher light output is attributed to enhanced reflectivity of the Al-based ODR in the near-ultraviolet wavelength range.