MOCVD growth and characterization of polar, semi-polar and non-polar AlGaN-based materials for making UV-LEDs

摘要

The effects of Si-doping on the properties of the AlGaN-based epi-layers grown on polar, semi-polar, and non-polar sapphire substrates by MOCVD were studied with XRD, SEM, hall effect, and Raman spectroscopy. The characterization results showed that both the surface morphology and the crystal quality of the polar AlGaN samples grown on a-plane sapphire substrates were improved with increasing Si dopant. It was found that the Si-induced strain relaxation in the non-polar AlGaN samples was promoted by the structural anisotropy as compared with the polar counterparts.