为了制作高亮度LED，需要在图形化蓝宝石衬底上生长GaN材料。通过光刻在平坦蓝宝石衬底上制作掩膜图形，通过刻蚀将图形转移到蓝宝石衬底，得到图形化蓝宝石衬底。在图形化蓝宝石衬底上进行GaN的侧向外延生长，并做后续处理，就制成了基于图形化蓝宝石衬底的高亮度LED。图形化蓝宝石衬底上GaN的侧向外延生长使得外延材料的位错密度从1010 cm-2降低到107 cm-2，这减少了发生非辐射复合的载流子，多量子阱发射更多的光子，LED的内量子效率提高。此外，图形化蓝宝石衬底能够有效散射从多量子阱射出的光线，使得出射光射到逃离区的几率更大，从而提高光萃取率。内量子效率和光萃取率的提高大大改善了LED的光电特性。

In order to make high-brightness LED, patterned sapphire substrate (PSS) is adopted. To make PSS, the first step is to make patterned mask on the planar sapphire substrate, and the second step is to copy the pattern of mask onto the sapphire substrate through etching. To make GaN grow on PSS by epitaxial lateral overgrowth and do subsequent processing, HB-LED based on PSS can be fabricated. The dislocation density of GaN on PSS is decreased from 1010 cm-2 to 107 cm-2, compared with the density of GaN on the planar sapphire substrate. The decrease of dislocation density of GaN decreases the number of carrier which vanish through the nonradiative recombination. Therefore, more photons are emitted from the multi-quantum well (MQW), and the internal quantum efficiency of LED is increased. Furthermore, PSS can effectively scatter the beam of light from the MQW, which increases the probability of light in escaping area, so the extraction rate of LED is enhanced. The combination of the enhancement of internal quantum efficiency and extraction rate greatly improves the photoelectrical characteristic of LED.