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.