Structural defects of cubic InGaN/GaN heterostructure grown on GaAs(001) substrate by MOVPE

Cubic InGaN/GaN heterostructures were grown on GaAs(001) substrates by MOVPE. X-ray reciprocal space mapping (RSM) measurements were used to investigate the structural defects. It was revealed that the cubic InGaN layers contained high density stacking faults parallel to the cubic InGaN {111} planes, and hexagonal domains with their c-axes parallel to the cubic InGaN 〈111〉 directions. The hexagonal domains were preferentially oriented to the cubic InGaN 〈111〉A directions rather than the 〈111〉B directions. It was clarified that the cubic InGaN layer was anisotropically strained, and this would be originated from the anisotropic mixing of the hexagonal phase in the cubic InGaN epilayers.