Characteristic comparison between GaN layer grown on c-plane cone shape patterned sapphire substrate and planar c-plane sapphire substrate by HVPE

It is suggested that the structural defects for the sample B were merged in the top region of the pattern during the 1st growth step and TDs were reduced or suppressed during the 2nd growth step in top region of the pattern. The GaN layer grown on PSS (Sample B) exhibited better optical properties and crystal quality than the GaN layer grown on planar c-plane sapphire (Sample A).