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.