SiN $_{\rm x}$ Nanopillars on GaN-Based LED to Enhance Light-Extraction Efficiency by a Successive Ionic Layer Adsorption and Reaction Method

This study presents a cost-effective method of producing SiN_x nanopillars on the surfaces of GaN LEDs to enhance light extraction using successive ionic layer adsorption and reaction (SILAR). The size and density distribution of ZnO nanoparticles deposited on SiN_x can be controlled by altering the ratio of water and ethylene glycol during SILAR. The nanoparticles are then used as an etching mask during ICP etching of the SiN_x film. Compared to traditional GaN-based LEDs, the proposed LEDs with SiN_x nanopillars increased light output power by 7.5%-15.2% at 20 mA. This improvement can be attributed mainly to a reduction in Fresnel reflection and increased scattering caused by the addition of SiN_x nanopillars across the emission surface of GaN LEDs.