MOVPE growth of GaN on a misoriented sapphire substrate

Abstract

The effects of slight misorientation from a (0001) singular plane on sapphire (α-Al2O3) substrates on the surface morphology and luminescence properties of MOVPE-grown GaN films have been studied. Macrostep morphology with periodic terraces (singular plane) and risers (clustered steps) has been observed for the first time on epitaxial GaN films grown on 3°-10° misoriented sapphire substrates toward both the [1010]sapphire and [1210]sapphire directions. In addition, it is found that the macrostep causes inhomogeneity of cathodoluminescence (CL) and electroluminescence (EL) patterns in Zn-doped GaN films, suggesting that the Zn-luminescence center formation depends on the growth planes of the terrace and riser. © 1991.