Nano-grooves etching on top of GaN-LED for light extraction enhancement

摘要

Nano-grooves etched through top p-GaN layer were proposed to promote GaN-LED light extraction of small angles. The properties of grating with an optimized period of 500 nm were investigated theoretically and experimentally. The extraction efficiency increased by 50% in the +/- 10 degrees incident angle range was verified by finite element modeling and rigorous coupled-wave analysis simulations, and sufficiently explained by transmission diffractive grating theory. The GaN-LED with a depth and period of 120 nm and 500 nm, respectively, etched inside a 20 mu m diameter ring contact was fabricated and characterized by atomic force microscopy and electroluminescence testing, and the obtained results were in agreement with the design and simulations.