High-quality {20-21} GaN layers on patterned sapphire substrate with wide-terrace

A {20-21} GaN layer was grown from a c-plane-like sapphire sidewall of a {22-43} patterned sapphire substrate according to the epitaxial relationship between c-GaN and c-sapphire despite {20-21} GaN is not growing on {22-43} sapphire. The as-grown {20-21} GaN layer had an m- and {10-11} facet structure. To improve the {20-21} GaN layer, a wide-terrace was attempted. The defects in the GaN layer were clustered on the m-facets, resulting in a dislocation density of less than 5.6 × 10⁵/cm² on the {10-11} facets. The {20-21} GaN layer had an excellent photoluminescence spectrum indicating a small number of defects.