Metalorganic vapor phase epitaxial growth, using di-isopropyl-telluride and dimethyl-zinc precursors, was investigated by studying the epilayer growth rate as a function of the growth temperature and precursor transport rates. The dependence of the growth rate upon the growth conditions was explained in terms of surface adsorption-desorption reactions; assuming that the incorporation of Zn and Te atoms took place via their selective adsorption at various surface lattice sites. Photoluminescence and absorption measurements led to the identification of 2 new donor-acceptor pair bands. These originated from the recombination of a Ga donor with 2 acceptor centers. The ionization energy for the higher-energy band was 0.056eV, and that for the lower-energy band was 0.140 to 0.150eV. Hall measurements revealed that the 0.056eV acceptor was responsible for the p-type conductivity of the layers. It was shown that C was incorporated as an acceptor and created the donor-acceptor bands that were seen in the photoluminescence spectra. The acceptor with the 0.056eV ionization energy was tentatively attributed to substitutional C atoms on Te lattice sites.

N.Lovergine, M.Longo, P.Prete, C.Gerardi, L.Calcagnile, R.Cingolani, A.M.Mancini: Journal of Applied Physics, 1997, 81[2], 685-92