Improved light output power of LEDs with embedded air voids structure and SiO2 current blocking layer

GaN-based light-emitting diodes (LEDs) with an embedded air voids structure and a SiO2 current blocking layer (CBL) was fabricated and investigated. The air voids structure was formed between cone-shaped patterned sapphire substrate and GaN epitaxial layer by combining laser scribing with H3PO4-based hot chemical etching. The air voids embedded high power LED showed 8.9% higher light output power due to a strong light reflection and redirection at the interface between GaN and air voids, which could increase the top light extraction of the high power LED. Compared to the air voids embedded high power LED, the light output power of the high power LED by integrating air voids structure with SiO2 CBL was 9.1% higher than that of the air voids embedded LED without SiO2 CBL. It was also found that the simulation results agree well with the experimental results.