Multiple Nanostructures on Full Surface of GZO/GaN-Based LED to Enhance Light-Extraction Efficiency Using a Solution-Based Method

This paper reports a solution-based method for the application of multiple nanostructures on full surface of GZO/GaN-based LEDs to enhance light-extraction efficiency. Ga-doped ZnO (GZO) was deposited to a thickness of 1μm and an n⁺-InGaN/GaN short-period superlattice structure was grown to improve the electrical characteristics of the LEDs, including series resistance and operating voltage. A solution-based method was used to control the density of ZnO nanoparticles deposited on the SiO₂ layer for use as self-assembled etching nanomasks. Multiple nanostructures were simultaneously formed on the surfaces of GZO, p-GaN, and n-GaN by dry etching. The proposed LEDs increase light output power by 10%-27% (at 20 mA) over that of regular GaN-based LEDs. The difference in light output power can be attributed to differences in the shape, thickness, and density of GZO and GaN nanostructures, resulting in a reduction in Fresnel reflection provided by the roughened surface of the GaN-based LEDs.