CHEMICAL ORDERING IN WURTZITE INXGA1-XN LAYERS GROWN ON (0001)-SAPPHIRE BY METALORGANIC VAPOR-PHASE EPITAXY

A diffraction analysis in the transmission electron microscope was car ried out on InxGa1-xN layers grown on (0001) sapphire by metalorganic vapor phase epitaxy on top of thick GaN buffer layers. It is found tha t the ternary InxGa1-xN layers can be chemically ordered. The In and G a atoms occupy, respectively, the two simple hexagonal sublattice site s related by the glide mirrors and helicoidal axes of the P6(3) mc sym metry group of the wurtzite GaN, The symmetry of the ordered ternary i s subsequently lowered by the disappearance of these operations, and i t is shown to agree with the P3ml space group. (C) 1998 American Insti tute of Physics. [S0003-6951(98)01714-8].