Enhanced Optical Property of InGaN Light-Emitting Diodes with SiO2 Nano-Bowl Photonic Crystal by Nanosphere Lithography

Abstract

The InGaN-based light-emitting diodes (LEDs) incorporating SiO2 nano-bowl photonic crystal (SNPC) arrays with different periods onto the indium-tin oxide (ITO) layers have been fabricated using nano-sphere lithography (NSL). A monolayer of self-assembled nano-spheres has served as a hard mold for pattern transfer to the SiO2 layer, leaving the ITO layer intact and free of etching damages. The LEDs with SNPC arrays have exhibited enhancement of the light output power (LOP) by 42% and reduction of the emission divergence angle by 22.5° compared with the conventional LEDs. Their optical performances and mechanisms have been investigated with finite-difference time-domain (FDTD) simulations.