Abstract
GaN material has a great development space for blue LED. However, lattice mismatch exists between GaN and substrate material, so it is restricted to be used. Recently, GaN-based LED grown on a patterned sapphire substrate (PSS) is widely studied. It can not only efficiently reduce threading dislocation (TD) density of GaN grown on, but also enhance light extraction efficiency as well. We successfully fabricate PSS of different scales by nanosphere lithography and compare the characteristics of GaN on each substrate. We compared the quality of GaN films grown on them by PL and XRD. The results indicate that the quality is the best when grown on pattered sapphire substrates with period 100 nm and duty ratio 100%. The results match. We can conclude that the quality of GaN films is better when grown on PSS with smaller period and larger duty ratio.