Effect of patterned ion-implanted sapphire on ultraviolet light-emitting diodes

Ultraviolet (UV) light-emitting diodes (LEDs) were fabricated on patterned-ion-implanted sapphire (PIIS) substrates using metalorganic chemical vapor deposition. The crystal qualities of the n-GaN epilayer grown on the patterned-N⁺-ionimplanted sapphire substrate were improved compared with that of the n-GaN epilayer grown on a conventional sapphire substrate. The optical properties of the undoped GaN and n-GaN epilayers grown on the PIIS substrate were improved. The light intensity of the UV LED at 100mA on the PIIS chip was 78% higher than that of the conventional LED. This increase in light intensity is due to the relaxation of the misfit strain at high temperature and the contribution of the internal free energies to the enhancement in structural and optical properties.