Raman scattering, photoluminescence, and X-ray diffraction studies of GaN layers grown on misoriented sapphire substrates

Photoluminescence, Raman scattering and X-ray diffraction experiments were performed on GaN films grown by metalorganic chemical vapor deposition on misoriented sapphire substrates. Sapphire substrates misoriented up to 6° from the a-plane were used in this study. An increased photoluminescence intensity was observed for layers grown on substrates having miscut angles of ∼3° indicating improvements in the crystalline quality, supported by X-ray diffraction and Raman scattering results. The GaN layers also show a minimum in compressive stress when grown on ∼3° misoriented sapphire substrates.