We demonstrated GaN-based light emitting diodes (LEDs) with different embedded heights of SiO2 pillars and air gap array structures. The air gap on top of the SiO2 pillars were also realized using the enhanced epitaxial lateral overgrowth mode. With the embedded SiO2 pillars and air gap array structures, we achieved a smaller reverse leakage current due to the lateral growth-induced crystal quality improvement. Moreover, under 20 mA current injections, the output powers were 3.04, 4.23, 4.66, and 4.44 mW for conventional LED, LEDs with embedded 200 and 500 nm height of SiO2 pillars and air gaps, 500 nm height of SiO2 pillars and air gaps, and 700 and 400 nm height of SiO2 pillars and air gaps, respectively. We found that the embedded 500 nm height SiO2 pillars and 500 nm height air gap array structures could enhance LED output power by more than 50% due to the enhanced guided-light scattering efficiency in our study.
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