Light Output Extraction Enhancement in GaN-Based Green LEDs With Periodic AZO Subwavelength Nanostructure Arrays

We experimentally and theoretically demonstrate the enhancement in the light extraction efficiency of InGaN/GaN multiple quantum well green light-emitting diodes (LEDs) through periodic aluminum-doped zinc oxide (AZO) subwavelength nanostructure arrays (SNAs). The AZO SNAs are formed on the surface of indium tin oxide electrodes of LEDs by laser interference lithography and a subsequent dry etching after AZO film deposition. For LEDs with AZO SNAs, the light output power is increased by 19% at 100 mA compared to the conventional LED on patterned sapphire substrate. Also, there is no distinct degradation in the electrical characteristics of LEDs.