High-quality GaN on intentionally roughened c-sapphire

Maskless lateral epitaxial over growth of GaN films on in situ etched sapphire substrates by metalorganic chemical vapor deposition

“…The effect of nano-craters on the growth is unclear. However, it has been found that such nano-craters would not have the inverse effect on the quality of GaN epilayers [8], and the existence of these nano-craters could help to improve the light extraction efficiency of the GaN-based LEDs [7].…”