GaN-based LEDs grown on Si-implanted GaN templates form air gaps beneath the active layer to enhance light-extraction efficiency. GaN-based epitaxial layers grown on selective Si-implanted regions had lower growth rates compared with those grown on implantation-free regions, resulting in selective growth and the subsequent over the Si-implanted regions. Accordingly, air gaps were formed over the Si-implanted regions after the meeting of laterally growing GaN facet fronts. The experimental results indicate that the light-output power of the LEDs grown on the Si-implanted GaN templates was enhanced by 36% compared with conventional LEDs. This enhancement in output power was attributed mainly to the air gaps, which led to a higher escape probability for the photons.