Inverse GaN Pyramids for Semipolar GaInN/GaN Light-Emitting Diodes

Excellent semipolar GaN material quality can be obtained by growing inverse GaN pyramids on full 2 inch c-plane sapphire when combining the advantages of defect reduction via FACELO and selective area growth for faceted surfaces. The nearly defect free material is obtained by structuring the mask into a honeycomb pattern. When realizing full GaInN/GaN LED structures on those templates, a relatively broad emission is observed during electroluminescence measurements. Furthermore, the dominant wavelength is found to be dependent on the applied current density. The pronounced shift is in good agreement with the wavelength shift along one single facet. Gas phase diffusion during the active area growth is believed to be the main reason for the varying indium content. The homogeneity could be influenced by changing the reactor pressure during the active area growth.