Growth of high quality Al0.22Ga0.78As layers on Si substrates by metalorganic chemical vapor deposition

High quality epitaxial layers of Al0.22Ga0.78As have been grown on Si substrates by adopting thermal cycle annealing. The quality of the Al0.22Ga0.78As has been assessed by photoluminescence, deep-level transient spectroscopy, and double-crystal x-ray diffraction studies. The emergence of a new luminescence emission (1.718 eV), high concentrations of shallow levels, passivation of a deep level (0.43 eV), and dislocation reduction in the high-temperature thermal cycle annealed samples have been explained by a silicon diffusion mechanism and the formation of complex point defects. Deep-level emission at 0.64 eV has been attributed to disordering in the epitaxial layers.