HIGH PERFORMANCE GAN-BASED LEDS ON PATTERNED SAPPHIRE SUBSTRATE WITH A NOVEL HYBRID PATTERNED SIO_2/AL_2O_3 PASSIVATION LAYER AND TIO_2/AL_2O_3 DBR BACKSIDE REFLECTOR

摘要

GaN-based light-emitting diodes (LEDs) on patterned sapphire substrate (PSS) with patterned SiO_2/Al_2O_3 passivation layer and TiO_2/Al_2O_3 distributed Bragg reflector (DBR) backside reflector have been proposed and fabricated. Highly passivated Al_2O_3 layer deposited on indium tin oxide (ITO) layer with excellent uniformity and quality has been achieved with atomic layer deposition (ALD) technology. With a 60 mA injection current, an enhancement of 21.6 %, 59.7 %, and 63.4 % in the LOP at 460 nm wavelength was realized for the LED with the patterned SiO_2/Al_2O_3 passivation layer, the LED with the patterned SiO_2/Al_2O_3 passivation layer and Ag mirror+3-pair TiO_2/SiO_2 DBR backside reflector, and the LED with the patterned SiO_2/Al_2O_3 passivation layer and Ag mirror+3-pair ALD-grown TiO_2/Al_2O_3 DBR backside reflector as compared with the conventional LED only with a single SiO_2 passivation layer, respectively.