GaN-Based LEDs With Air Voids Prepared by Laser Scribing and Chemical Etching
The authors report the formation of air-void sa t the GaN/cone-shaped-patterned-sapphire-substrate interface by laser scribing and lateral etching with one-step growth. With 5- and 20-min lateral etching, it was found that pyramid-like air-void was formed with an average height of 0.98 and 1.9 m, respectively, on top of each corn of the substrate. It was also found that we can en- hance output power of GaN-based light-emitting diodes by 6.6% and 11.5%, respectively, by immersing the wafer in a mixture of H PO and H SO solution at 220 C for 5 and 20 min, respec- tively. IndexTerms—GaN,laserscribing,lateraletching,light-emitting diodes (LEDs).