Fabrication of GaN structures with embedded network of voids using pillar patterned GaN templates

In this paper we report on the MOCVD growth and characterization of GaN structures and InGaN single quantum wells grown on pillar patterned GaN/sapphire templates. During the regrowth a network of voids was intentionally formed at the interface of sapphire substrate and GaN epitaxial layer. The regrowth process was found to decrease the threading dislocation density of the overgrown layer. The quantum well sample grown on patterned template showed significantly higher optical output in photoluminescence measurements compared to the reference sample with identical internal quantum efficiency characteristics. We attribute the increase to enhanced light extraction efficiency caused by strong scattering and redirection of light from the scattering elements.

► GaN structures and single quantum wells with embedded network of voids were fabricated. ► Threading dislocation density decreased with the process. ► Light extraction efficiency of the quantum well increased due to increased scattering and redirection of light.